From 7bf136b501fef3e189b45091e8a4757a5eaef31f Mon Sep 17 00:00:00 2001
From: Beartama <8091245+uyha@users.noreply.github.com>
Date: Tue, 14 Nov 2023 23:52:15 +0200
Subject: [PATCH] Add JSON reporter (#2706)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Martin Hořeňovský <martin.horenovsky@gmail.com>
---
 src/CMakeLists.txt                            |   4 +
 src/catch2/catch_all.hpp                      |   1 +
 src/catch2/internal/catch_jsonwriter.cpp      | 115 +++++
 src/catch2/internal/catch_jsonwriter.hpp      | 123 ++++++
 .../internal/catch_reporter_registry.cpp      |   5 +-
 src/catch2/meson.build                        |   4 +
 src/catch2/reporters/catch_reporter_json.cpp  | 395 ++++++++++++++++++
 src/catch2/reporters/catch_reporter_json.hpp  |  95 +++++
 src/catch2/reporters/catch_reporters_all.hpp  |   1 +
 tests/CMakeLists.txt                          |   6 +-
 .../Baselines/automake.sw.approved.txt        |   1 +
 .../Baselines/automake.sw.multi.approved.txt  |   1 +
 .../Baselines/compact.sw.approved.txt         | 135 +++++-
 .../Baselines/compact.sw.multi.approved.txt   | 135 +++++-
 .../Baselines/console.std.approved.txt        |   4 +-
 .../Baselines/console.sw.approved.txt         | 316 +++++++++++++-
 .../Baselines/console.sw.multi.approved.txt   | 316 +++++++++++++-
 .../SelfTest/Baselines/junit.sw.approved.txt  |  15 +-
 .../Baselines/junit.sw.multi.approved.txt     |  15 +-
 .../Baselines/sonarqube.sw.approved.txt       |  15 +
 .../Baselines/sonarqube.sw.multi.approved.txt |  15 +
 tests/SelfTest/Baselines/tap.sw.approved.txt  |  34 +-
 .../Baselines/tap.sw.multi.approved.txt       |  34 +-
 .../Baselines/teamcity.sw.approved.txt        |   2 +
 .../Baselines/teamcity.sw.multi.approved.txt  |   2 +
 tests/SelfTest/Baselines/xml.sw.approved.txt  | 298 ++++++++++++-
 .../Baselines/xml.sw.multi.approved.txt       | 298 ++++++++++++-
 .../IntrospectiveTests/Json.tests.cpp         | 116 +++++
 .../IntrospectiveTests/Reporters.tests.cpp    |   4 +-
 29 files changed, 2484 insertions(+), 21 deletions(-)
 create mode 100644 src/catch2/internal/catch_jsonwriter.cpp
 create mode 100644 src/catch2/internal/catch_jsonwriter.hpp
 create mode 100644 src/catch2/reporters/catch_reporter_json.cpp
 create mode 100644 src/catch2/reporters/catch_reporter_json.hpp
 create mode 100644 tests/SelfTest/IntrospectiveTests/Json.tests.cpp

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4e3b3566..a70eef03 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -93,6 +93,7 @@ set(IMPL_HEADERS
   ${SOURCES_DIR}/internal/catch_getenv.hpp
   ${SOURCES_DIR}/internal/catch_istream.hpp
   ${SOURCES_DIR}/internal/catch_is_permutation.hpp
+  ${SOURCES_DIR}/internal/catch_jsonwriter.hpp
   ${SOURCES_DIR}/internal/catch_lazy_expr.hpp
   ${SOURCES_DIR}/internal/catch_leak_detector.hpp
   ${SOURCES_DIR}/internal/catch_list.hpp
@@ -177,6 +178,7 @@ set(IMPL_SOURCES
   ${SOURCES_DIR}/internal/catch_floating_point_helpers.cpp
   ${SOURCES_DIR}/internal/catch_getenv.cpp
   ${SOURCES_DIR}/internal/catch_istream.cpp
+  ${SOURCES_DIR}/internal/catch_jsonwriter.cpp
   ${SOURCES_DIR}/internal/catch_lazy_expr.cpp
   ${SOURCES_DIR}/internal/catch_leak_detector.cpp
   ${SOURCES_DIR}/internal/catch_list.cpp
@@ -289,6 +291,7 @@ set(REPORTER_HEADERS
   ${SOURCES_DIR}/reporters/catch_reporter_cumulative_base.hpp
   ${SOURCES_DIR}/reporters/catch_reporter_event_listener.hpp
   ${SOURCES_DIR}/reporters/catch_reporter_helpers.hpp
+  ${SOURCES_DIR}/reporters/catch_reporter_json.hpp
   ${SOURCES_DIR}/reporters/catch_reporter_junit.hpp
   ${SOURCES_DIR}/reporters/catch_reporter_multi.hpp
   ${SOURCES_DIR}/reporters/catch_reporter_registrars.hpp
@@ -307,6 +310,7 @@ set(REPORTER_SOURCES
   ${SOURCES_DIR}/reporters/catch_reporter_cumulative_base.cpp
   ${SOURCES_DIR}/reporters/catch_reporter_event_listener.cpp
   ${SOURCES_DIR}/reporters/catch_reporter_helpers.cpp
+  ${SOURCES_DIR}/reporters/catch_reporter_json.cpp
   ${SOURCES_DIR}/reporters/catch_reporter_junit.cpp
   ${SOURCES_DIR}/reporters/catch_reporter_multi.cpp
   ${SOURCES_DIR}/reporters/catch_reporter_registrars.cpp
diff --git a/src/catch2/catch_all.hpp b/src/catch2/catch_all.hpp
index cdef3946..a7969fef 100644
--- a/src/catch2/catch_all.hpp
+++ b/src/catch2/catch_all.hpp
@@ -74,6 +74,7 @@
 #include <catch2/internal/catch_getenv.hpp>
 #include <catch2/internal/catch_is_permutation.hpp>
 #include <catch2/internal/catch_istream.hpp>
+#include <catch2/internal/catch_jsonwriter.hpp>
 #include <catch2/internal/catch_lazy_expr.hpp>
 #include <catch2/internal/catch_leak_detector.hpp>
 #include <catch2/internal/catch_list.hpp>
diff --git a/src/catch2/internal/catch_jsonwriter.cpp b/src/catch2/internal/catch_jsonwriter.cpp
new file mode 100644
index 00000000..f6c279d8
--- /dev/null
+++ b/src/catch2/internal/catch_jsonwriter.cpp
@@ -0,0 +1,115 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#include <catch2/internal/catch_enforce.hpp>
+#include <catch2/internal/catch_jsonwriter.hpp>
+
+namespace Catch {
+    void JsonUtils::indent( std::ostream& os, std::uint64_t level ) {
+        for ( std::uint64_t i = 0; i < level; ++i ) {
+            os << "  ";
+        }
+    }
+    void JsonUtils::appendCommaNewline( std::ostream& os,
+                                        bool& should_comma,
+                                        std::uint64_t level ) {
+        if ( should_comma ) { os << ','; }
+        should_comma = true;
+        os << '\n';
+        indent( os, level );
+    }
+
+    JsonObjectWriter::JsonObjectWriter( std::ostream& os ):
+        JsonObjectWriter{ os, 0 } {}
+
+    JsonObjectWriter::JsonObjectWriter( std::ostream& os,
+                                        std::uint64_t indent_level ):
+        m_os{ os }, m_indent_level{ indent_level } {
+        m_os << "{";
+    }
+    JsonObjectWriter::JsonObjectWriter( JsonObjectWriter&& source ):
+        m_os{ source.m_os },
+        m_indent_level{ source.m_indent_level },
+        m_should_comma{ source.m_should_comma },
+        m_active{ source.m_active } {
+        source.m_active = false;
+    }
+
+    JsonObjectWriter::~JsonObjectWriter() {
+        if ( !m_active ) { return; }
+
+        m_os << '\n';
+        JsonUtils::indent( m_os, m_indent_level );
+        m_os << '}';
+    }
+
+    JsonValueWriter JsonObjectWriter::write( std::string const& key ) {
+        JsonUtils::appendCommaNewline(
+            m_os, m_should_comma, m_indent_level + 1 );
+
+        m_os << '"' << key << '"' << ": ";
+        return JsonValueWriter{ m_os, m_indent_level + 1 };
+    }
+
+    JsonArrayWriter::JsonArrayWriter( std::ostream& os ):
+        JsonArrayWriter{ os, 0 } {}
+    JsonArrayWriter::JsonArrayWriter( std::ostream& os,
+                                      std::uint64_t indent_level ):
+        m_os{ os }, m_indent_level{ indent_level } {
+        m_os << "[";
+    }
+    JsonArrayWriter::JsonArrayWriter( JsonArrayWriter&& source ):
+        m_os{ source.m_os },
+        m_indent_level{ source.m_indent_level },
+        m_should_comma{ source.m_should_comma },
+        m_active{ source.m_active } {
+        source.m_active = false;
+    }
+    JsonArrayWriter::~JsonArrayWriter() {
+        if ( !m_active ) { return; }
+
+        m_os << '\n';
+        JsonUtils::indent( m_os, m_indent_level );
+        m_os << ']';
+    }
+
+    JsonObjectWriter JsonArrayWriter::writeObject() {
+        JsonUtils::appendCommaNewline(
+            m_os, m_should_comma, m_indent_level + 1 );
+        return JsonObjectWriter{ m_os, m_indent_level + 1 };
+    }
+
+    JsonArrayWriter JsonArrayWriter::writeArray() {
+        JsonUtils::appendCommaNewline(
+            m_os, m_should_comma, m_indent_level + 1 );
+        return JsonArrayWriter{ m_os, m_indent_level + 1 };
+    }
+
+    JsonArrayWriter& JsonArrayWriter::write( bool value ) {
+        return writeImpl( value );
+    }
+
+    JsonValueWriter::JsonValueWriter( std::ostream& os ):
+        JsonValueWriter{ os, 0 } {}
+
+    JsonValueWriter::JsonValueWriter( std::ostream& os,
+                                      std::uint64_t indent_level ):
+        m_os{ os }, m_indent_level{ indent_level } {}
+
+    JsonObjectWriter JsonValueWriter::writeObject() && {
+        return JsonObjectWriter{ m_os, m_indent_level };
+    }
+
+    JsonArrayWriter JsonValueWriter::writeArray() && {
+        return JsonArrayWriter{ m_os, m_indent_level };
+    }
+
+    void JsonValueWriter::write( bool value ) && {
+        writeImpl( value ? "true" : "false", false );
+    }
+
+} // namespace Catch
diff --git a/src/catch2/internal/catch_jsonwriter.hpp b/src/catch2/internal/catch_jsonwriter.hpp
new file mode 100644
index 00000000..9cac3de6
--- /dev/null
+++ b/src/catch2/internal/catch_jsonwriter.hpp
@@ -0,0 +1,123 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#ifndef CATCH_JSONWRITER_HPP_INCLUDED
+#define CATCH_JSONWRITER_HPP_INCLUDED
+
+#include <catch2/internal/catch_reusable_string_stream.hpp>
+#include <catch2/internal/catch_stringref.hpp>
+
+#include <cstdint>
+#include <sstream>
+
+namespace Catch {
+    class JsonObjectWriter;
+    class JsonArrayWriter;
+
+    struct JsonUtils {
+        static void indent( std::ostream& os, std::uint64_t level );
+        static void appendCommaNewline( std::ostream& os,
+                                        bool& should_comma,
+                                        std::uint64_t level );
+    };
+
+    class JsonValueWriter {
+    public:
+        JsonValueWriter( std::ostream& os );
+        JsonValueWriter( std::ostream& os, std::uint64_t indent_level );
+
+        JsonObjectWriter writeObject() &&;
+        JsonArrayWriter writeArray() &&;
+
+        template <typename T>
+        void write( T const& value ) && {
+            writeImpl( value, !std::is_arithmetic<T>::value );
+        }
+
+        void write( bool value ) &&;
+
+    private:
+        template <typename T>
+        void writeImpl( T const& value, bool quote_value ) {
+            if ( quote_value ) { m_os << '"'; }
+            m_sstream << value;
+            while ( true ) {
+                char c = m_sstream.get();
+
+                if ( m_sstream.eof() ) { break; }
+                if ( c == '"' ) {
+                    m_os << '\\' << '"';
+                } else {
+                    m_os << c;
+                }
+            }
+            if ( quote_value ) { m_os << '"'; }
+        }
+
+        std::ostream& m_os;
+        std::stringstream m_sstream{};
+        std::uint64_t m_indent_level;
+    };
+
+    class JsonObjectWriter {
+    public:
+        JsonObjectWriter( std::ostream& os );
+        JsonObjectWriter( std::ostream& os, std::uint64_t indent_level );
+
+        JsonObjectWriter( JsonObjectWriter&& source );
+        JsonObjectWriter& operator=( JsonObjectWriter&& source ) = delete;
+
+        ~JsonObjectWriter();
+
+        JsonValueWriter write( std::string const& key );
+
+    private:
+        std::ostream& m_os;
+        std::uint64_t m_indent_level;
+        bool m_should_comma = false;
+        bool m_active = true;
+    };
+
+    class JsonArrayWriter {
+    public:
+        JsonArrayWriter( std::ostream& os );
+        JsonArrayWriter( std::ostream& os, std::uint64_t indent_level );
+
+        JsonArrayWriter( JsonArrayWriter&& source );
+        JsonArrayWriter& operator=( JsonArrayWriter&& source ) = delete;
+
+        ~JsonArrayWriter();
+
+        JsonObjectWriter writeObject();
+        JsonArrayWriter writeArray();
+
+        template <typename T>
+        JsonArrayWriter& write( T const& value ) {
+            return writeImpl( value );
+        }
+
+        JsonArrayWriter& write( bool value );
+
+    private:
+        template <typename T>
+        JsonArrayWriter& writeImpl( T const& value ) {
+            JsonUtils::appendCommaNewline(
+                m_os, m_should_comma, m_indent_level + 1 );
+            JsonValueWriter{ m_os }.write( value );
+
+            return *this;
+        }
+
+        std::ostream& m_os;
+        std::uint64_t m_indent_level;
+        bool m_should_comma = false;
+        bool m_active = true;
+    };
+
+} // namespace Catch
+
+#endif // CATCH_JSONWRITER_HPP_INCLUDED
diff --git a/src/catch2/internal/catch_reporter_registry.cpp b/src/catch2/internal/catch_reporter_registry.cpp
index b2b0cd07..cea8c4dc 100644
--- a/src/catch2/internal/catch_reporter_registry.cpp
+++ b/src/catch2/internal/catch_reporter_registry.cpp
@@ -6,13 +6,14 @@
 
 // SPDX-License-Identifier: BSL-1.0
 
-#include <catch2/internal/catch_reporter_registry.hpp>
 #include <catch2/interfaces/catch_interfaces_reporter_factory.hpp>
 #include <catch2/internal/catch_enforce.hpp>
 #include <catch2/internal/catch_move_and_forward.hpp>
+#include <catch2/internal/catch_reporter_registry.hpp>
 #include <catch2/reporters/catch_reporter_automake.hpp>
 #include <catch2/reporters/catch_reporter_compact.hpp>
 #include <catch2/reporters/catch_reporter_console.hpp>
+#include <catch2/reporters/catch_reporter_json.hpp>
 #include <catch2/reporters/catch_reporter_junit.hpp>
 #include <catch2/reporters/catch_reporter_registrars.hpp>
 #include <catch2/reporters/catch_reporter_sonarqube.hpp>
@@ -47,6 +48,8 @@ namespace Catch {
             Detail::make_unique<ReporterFactory<TeamCityReporter>>();
         m_impl->factories["XML"] =
             Detail::make_unique<ReporterFactory<XmlReporter>>();
+        m_impl->factories["JSON"] =
+            Detail::make_unique<ReporterFactory<JsonReporter>>();
     }
 
     ReporterRegistry::~ReporterRegistry() = default;
diff --git a/src/catch2/meson.build b/src/catch2/meson.build
index 1f9bf45a..09a3db1b 100644
--- a/src/catch2/meson.build
+++ b/src/catch2/meson.build
@@ -98,6 +98,7 @@ internal_headers = [
   'internal/catch_getenv.hpp',
   'internal/catch_istream.hpp',
   'internal/catch_is_permutation.hpp',
+  'internal/catch_jsonwriter.hpp',
   'internal/catch_lazy_expr.hpp',
   'internal/catch_leak_detector.hpp',
   'internal/catch_list.hpp',
@@ -214,6 +215,7 @@ internal_sources = files(
   'internal/catch_floating_point_helpers.cpp',
   'internal/catch_getenv.cpp',
   'internal/catch_istream.cpp',
+  'internal/catch_jsonwriter.cpp',
   'internal/catch_lazy_expr.cpp',
   'internal/catch_leak_detector.cpp',
   'internal/catch_list.cpp',
@@ -280,6 +282,7 @@ reporter_headers = [
   'reporters/catch_reporter_cumulative_base.hpp',
   'reporters/catch_reporter_event_listener.hpp',
   'reporters/catch_reporter_helpers.hpp',
+  'reporters/catch_reporter_json.hpp',
   'reporters/catch_reporter_junit.hpp',
   'reporters/catch_reporter_multi.hpp',
   'reporters/catch_reporter_registrars.hpp',
@@ -299,6 +302,7 @@ reporter_sources = files(
   'reporters/catch_reporter_cumulative_base.cpp',
   'reporters/catch_reporter_event_listener.cpp',
   'reporters/catch_reporter_helpers.cpp',
+  'reporters/catch_reporter_json.cpp',
   'reporters/catch_reporter_junit.cpp',
   'reporters/catch_reporter_multi.cpp',
   'reporters/catch_reporter_registrars.cpp',
diff --git a/src/catch2/reporters/catch_reporter_json.cpp b/src/catch2/reporters/catch_reporter_json.cpp
new file mode 100644
index 00000000..7ddc7036
--- /dev/null
+++ b/src/catch2/reporters/catch_reporter_json.cpp
@@ -0,0 +1,395 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+//
+#include <catch2/catch_test_case_info.hpp>
+#include <catch2/catch_test_spec.hpp>
+#include <catch2/catch_version.hpp>
+#include <catch2/interfaces/catch_interfaces_config.hpp>
+#include <catch2/internal/catch_list.hpp>
+#include <catch2/internal/catch_string_manip.hpp>
+#include <catch2/reporters/catch_reporter_json.hpp>
+
+namespace Catch {
+    namespace {
+        void writeSourceInfo( JsonObjectWriter& writer,
+                              SourceLineInfo const& sourceInfo ) {
+            auto source_location_writer =
+                writer.write( "source-location" ).writeObject();
+            source_location_writer.write( "filename" ).write( sourceInfo.file );
+            source_location_writer.write( "line" ).write( sourceInfo.line );
+        }
+
+        void writeTags( JsonArrayWriter writer, std::vector<Tag> const& tags ) {
+            for ( auto const& tag : tags ) {
+                writer.write( tag.original );
+            }
+        }
+
+        void writeProperties( JsonArrayWriter writer,
+                              TestCaseInfo const& info ) {
+            if ( info.isHidden() ) { writer.write( "is-hidden" ); }
+            if ( info.okToFail() ) { writer.write( "ok-to-fail" ); }
+            if ( info.expectedToFail() ) { writer.write( "expected-to-fail" ); }
+            if ( info.throws() ) { writer.write( "throws" ); }
+        }
+
+        //void writeCounts( JsonObjectWriter writer, Counts const& counts ) {
+        //    writer.write( "passed" ).write( counts.passed );
+        //    writer.write( "failed" ).write( counts.failed );
+        //    writer.write( "fail-but-ok" ).write( counts.failedButOk );
+        //    writer.write( "skipped" ).write( counts.skipped );
+        //}
+
+        //void writeTestInfo( JsonObjectWriter writer,
+        //                    TestCaseInfo const& info ) {
+        //    writer.write( "name" ).write( info.name );
+        //    writeTags( writer.write( "tags" ).writeArray(), info.tags );
+        //    writeSourceInfo( writer, info.lineInfo );
+        //    writeProperties( writer.write( "properties" ).writeArray(), info );
+        //}
+
+        //void writeSection( JsonObjectWriter& writer,
+        //                   CumulativeReporterBase::SectionNode const& section,
+        //                   bool selfWrite ) {
+        //    if ( selfWrite ) {
+        //        writer.write( "name" ).write( section.stats.sectionInfo.name );
+        //        writeSourceInfo( writer, section.stats.sectionInfo.lineInfo );
+        //        writeCounts( writer.write( "assertions-stats" ).writeObject(),
+        //                     section.stats.assertions );
+        //    }
+        //    if ( section.childSections.empty() ) { return; }
+        //    auto sectionsWriter = writer.write( "sections" ).writeArray();
+        //    for ( auto const& childPtr : section.childSections ) {
+        //        auto childSectionWriter = sectionsWriter.writeObject();
+        //        writeSection( childSectionWriter, *childPtr, true );
+        //    }
+        //}
+    } // namespace
+
+    JsonReporter::JsonReporter( ReporterConfig&& config ):
+        StreamingReporterBase{ CATCH_MOVE( config ) } {
+
+        m_preferences.shouldRedirectStdOut = true;
+        // TBD: Do we want to report all assertions? XML reporter does
+        //      not, but for machine-parseable reporters I think the answer
+        //      should be yes.
+        m_preferences.shouldReportAllAssertions = true;
+
+        m_objectWriters.emplace( m_stream );
+        m_writers.emplace( Writer::Object );
+        auto& writer = m_objectWriters.top();
+
+        writer.write( "version" ).write( 1 );
+
+        {
+            auto metadata_writer = writer.write( "metadata" ).writeObject();
+            metadata_writer.write( "name" ).write( m_config->name() );
+            metadata_writer.write( "rng-seed" ).write( m_config->rngSeed() );
+            metadata_writer.write( "catch2-version" ).write( libraryVersion() );
+            if ( m_config->testSpec().hasFilters() ) {
+                metadata_writer.write( "filters" )
+                    .write( m_config->testSpec() );
+            }
+        }
+    }
+
+    JsonReporter::~JsonReporter() {
+        endListing();
+        // TODO: Ensure this closes the top level object, add asserts
+        assert( m_writers.size() == 1 && "Only the top level object should be open" );
+        assert( m_writers.top() == Writer::Object );
+        endObject();
+        m_stream << '\n' << std::flush;
+        assert( m_writers.empty() );
+    }
+
+    JsonArrayWriter& JsonReporter::startArray() {
+        m_arrayWriters.emplace( m_arrayWriters.top().writeArray() );
+        m_writers.emplace( Writer::Array );
+        return m_arrayWriters.top();
+    }
+    JsonArrayWriter& JsonReporter::startArray( std::string const& key ) {
+        m_arrayWriters.emplace(
+            m_objectWriters.top().write( key ).writeArray() );
+        m_writers.emplace( Writer::Array );
+        return m_arrayWriters.top();
+    }
+
+    JsonObjectWriter& JsonReporter::startObject() {
+        m_objectWriters.emplace( m_arrayWriters.top().writeObject() );
+        m_writers.emplace( Writer::Object );
+        return m_objectWriters.top();
+    }
+    JsonObjectWriter& JsonReporter::startObject( std::string const& key ) {
+        m_objectWriters.emplace(
+            m_objectWriters.top().write( key ).writeObject() );
+        m_writers.emplace( Writer::Object );
+        return m_objectWriters.top();
+    }
+
+    void JsonReporter::endObject() {
+        assert( isInside( Writer::Object ) );
+        m_objectWriters.pop();
+        m_writers.pop();
+    }
+    void JsonReporter::endArray() {
+        assert( isInside( Writer::Array ) );
+        m_arrayWriters.pop();
+        m_writers.pop();
+    }
+
+    bool JsonReporter::isInside( Writer writer ) {
+        return !m_writers.empty() && m_writers.top() == writer;
+    }
+
+    void JsonReporter::startListing() {
+        if ( !m_startedListing ) { startObject( "listings" ); }
+        m_startedListing = true;
+    }
+    void JsonReporter::endListing() {
+        if ( m_startedListing ) { endObject(); }
+        m_startedListing = false;
+    }
+
+    std::string JsonReporter::getDescription() {
+        return "WIP! Reports test results as a JSON document. WIP!";
+    }
+
+    void JsonReporter::testRunStarting( TestRunInfo const& testInfo ) {
+        StreamingReporterBase::testRunStarting( testInfo );
+        endListing();
+
+        assert( isInside( Writer::Object ) );
+        startObject( "test-run" );
+        startArray( "test-cases" );
+    }
+
+     static void writeCounts( JsonObjectWriter&& writer, Counts const& counts ) {
+        writer.write( "passed" ).write( counts.passed );
+        writer.write( "failed" ).write( counts.failed );
+        writer.write( "fail-but-ok" ).write( counts.failedButOk );
+        writer.write( "skipped" ).write( counts.skipped );
+    }
+
+    void JsonReporter::testRunEnded(TestRunStats const& runStats) {
+        assert( isInside( Writer::Array ) );
+        // End "test-cases"
+        endArray();
+
+        {
+            auto totals = m_objectWriters.top().write( "totals" ).writeObject();
+            writeCounts( totals.write( "assertions" ).writeObject(),
+                         runStats.totals.assertions );
+            writeCounts( totals.write( "test-cases" ).writeObject(),
+                         runStats.totals.testCases );
+        }
+
+        // End the "test-run" object
+        endObject();
+    }
+
+    void JsonReporter::testCaseStarting( TestCaseInfo const& tcInfo ) {
+        StreamingReporterBase::testCaseStarting( tcInfo );
+
+        assert( isInside( Writer::Array ) &&
+                "We should be in the 'test-cases' array" );
+        startObject();
+        // "test-info" prelude
+        {
+            auto testInfo =
+                m_objectWriters.top().write( "test-info" ).writeObject();
+            // TODO: handle testName vs className!!
+            testInfo.write( "name" ).write( tcInfo.name );
+            writeSourceInfo(testInfo, tcInfo.lineInfo);
+            writeTags( testInfo.write( "tags" ).writeArray(), tcInfo.tags );
+            writeProperties( testInfo.write( "properties" ).writeArray(),
+                             tcInfo );
+        }
+
+
+        // Start the array for individual test runs (testCasePartial pairs)
+        startArray( "runs" );
+    }
+
+    void JsonReporter::testCaseEnded( TestCaseStats const& tcStats ) {
+        StreamingReporterBase::testCaseEnded( tcStats );
+
+        // We need to close the 'runs' array before finishing the test case
+        assert( isInside( Writer::Array ) );
+        endArray();
+
+        {
+            auto totals = m_objectWriters.top().write( "totals" ).writeObject();
+            writeCounts( totals.write( "assertions" ).writeObject(),
+                         tcStats.totals.assertions );
+            // We do not write the test case totals, because there will always be just one test case here.
+            // TODO: overall "result" -> success, skip, fail here? Or in partial result?
+        }
+        // We do not write out stderr/stdout, because we instead wrote those out in partial runs
+
+        // TODO: aborting?
+
+        // And we also close this test case's object
+        assert( isInside( Writer::Object ) );
+        endObject();
+    }
+
+    void JsonReporter::testCasePartialStarting( TestCaseInfo const& /*tcInfo*/,
+                                                uint64_t index ) {
+        startObject();
+        m_objectWriters.top().write( "run-idx" ).write( index );
+        startArray( "path" );
+        //startObject( "path" );
+        // TODO: we want to delay most of the printing to the 'root' section
+        // TODO: childSection key name?
+    }
+
+    void JsonReporter::testCasePartialEnded( TestCaseStats const& tcStats,
+                                             uint64_t /*index*/ ) {
+        // Fixme: the top level section handles this.
+        //// path object
+        endArray();
+        if ( !tcStats.stdOut.empty() ) {
+            m_objectWriters.top()
+                .write( "captured-stdout" )
+                .write( tcStats.stdOut );
+        }
+        if ( !tcStats.stdErr.empty() ) {
+            m_objectWriters.top()
+                .write( "captured-stderr" )
+                .write( tcStats.stdErr );
+        }
+        {
+            auto totals = m_objectWriters.top().write( "totals" ).writeObject();
+            writeCounts( totals.write( "assertions" ).writeObject(),
+                         tcStats.totals.assertions );
+            // We do not write the test case totals, because there will
+            // always be just one test case here.
+            // TODO: overall "result" -> success, skip, fail here? Or in
+            // partial result?
+        }
+        // TODO: aborting?
+        // run object
+        endObject();
+    }
+
+    void JsonReporter::sectionStarting( SectionInfo const& sectionInfo ) {
+        assert( isInside( Writer::Array ) &&
+                "Section should always start inside an object" );
+        // We want to nest top level sections, even though it shares name
+        // and source loc with the TEST_CASE
+        auto& sectionObject = startObject();
+        sectionObject.write( "kind" ).write( "section" );
+        sectionObject.write( "name" ).write( sectionInfo.name );
+        writeSourceInfo( m_objectWriters.top(), sectionInfo.lineInfo );
+
+
+        // TBD: Do we want to create this event lazily? It would become
+        //      rather complex, but we could do it, and it would look
+        //      better for empty sections. OTOH, empty sections should
+        //      be rare.
+        startArray( "path" );
+    }
+    void JsonReporter::sectionEnded( SectionStats const& /*sectionStats */) {
+        // End the subpath array
+        endArray();
+        // TODO: metadata
+        // TODO: what info do we have here?
+
+        // End the section object
+        endObject();
+    }
+
+    void JsonReporter::assertionStarting( AssertionInfo const& /*assertionInfo*/ ) {}
+    void JsonReporter::assertionEnded( AssertionStats const& assertionStats ) {
+        // TODO: There is lot of different things to handle here, but
+        //       we can fill it in later, after we show that the basic
+        //       outline and streaming reporter impl works well enough.
+        //if ( !m_config->includeSuccessfulResults()
+        //    && assertionStats.assertionResult.isOk() ) {
+        //    return;
+        //}
+        assert( isInside( Writer::Array ) );
+        auto assertionObject = m_arrayWriters.top().writeObject();
+
+        assertionObject.write( "kind" ).write( "assertion" );
+        writeSourceInfo( assertionObject,
+                         assertionStats.assertionResult.getSourceInfo() );
+        assertionObject.write( "status" )
+            .write( assertionStats.assertionResult.isOk() );
+        // TODO: handling of result.
+        // TODO: messages
+        // TODO: totals?
+    }
+
+
+    void JsonReporter::benchmarkPreparing( StringRef name ) { (void)name; }
+    void JsonReporter::benchmarkStarting( BenchmarkInfo const& ) {}
+    void JsonReporter::benchmarkEnded( BenchmarkStats<> const& ) {}
+    void JsonReporter::benchmarkFailed( StringRef error ) { (void)error; }
+
+    void JsonReporter::listReporters(
+        std::vector<ReporterDescription> const& descriptions ) {
+        startListing();
+
+        auto writer = m_objectWriters.top().write( "reporters" ).writeArray();
+        for ( auto const& desc : descriptions ) {
+            auto desc_writer = writer.writeObject();
+            desc_writer.write( "name" ).write( desc.name );
+            desc_writer.write( "description" ).write( desc.description );
+        }
+    }
+    void JsonReporter::listListeners(
+        std::vector<ListenerDescription> const& descriptions ) {
+        startListing();
+
+        auto writer = m_objectWriters.top().write( "listeners" ).writeArray();
+
+        for ( auto const& desc : descriptions ) {
+            auto desc_writer = writer.writeObject();
+            desc_writer.write( "name" ).write( desc.name );
+            desc_writer.write( "description" ).write( desc.description );
+        }
+    }
+    void JsonReporter::listTests( std::vector<TestCaseHandle> const& tests ) {
+        startListing();
+
+        auto writer = m_objectWriters.top().write( "tests" ).writeArray();
+
+        for ( auto const& test : tests ) {
+            auto desc_writer = writer.writeObject();
+            auto const& info = test.getTestCaseInfo();
+
+            desc_writer.write( "name" ).write( info.name );
+            desc_writer.write( "class-name" ).write( info.className );
+            {
+                auto tag_writer = desc_writer.write( "tags" ).writeArray();
+                for ( auto const& tag : info.tags ) {
+                    tag_writer.write( tag.original );
+                }
+            }
+            writeSourceInfo( desc_writer, info.lineInfo );
+        }
+    }
+    void JsonReporter::listTags( std::vector<TagInfo> const& tags ) {
+        startListing();
+
+        auto writer = m_objectWriters.top().write( "tags" ).writeArray();
+        for ( auto const& tag : tags ) {
+            auto tag_writer = writer.writeObject();
+            {
+                auto aliases_writer =
+                    tag_writer.write( "aliases" ).writeArray();
+                for ( auto alias : tag.spellings ) {
+                    aliases_writer.write( alias );
+                }
+            }
+            tag_writer.write( "count" ).write( tag.count );
+        }
+    }
+} // namespace Catch
diff --git a/src/catch2/reporters/catch_reporter_json.hpp b/src/catch2/reporters/catch_reporter_json.hpp
new file mode 100644
index 00000000..33a43613
--- /dev/null
+++ b/src/catch2/reporters/catch_reporter_json.hpp
@@ -0,0 +1,95 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#ifndef CATCH_REPORTER_JSON_HPP_INCLUDED
+#define CATCH_REPORTER_JSON_HPP_INCLUDED
+
+#include <catch2/catch_timer.hpp>
+#include <catch2/internal/catch_jsonwriter.hpp>
+#include <catch2/reporters/catch_reporter_streaming_base.hpp>
+
+#include <stack>
+
+namespace Catch {
+    class JsonReporter : public StreamingReporterBase {
+    public:
+        JsonReporter( ReporterConfig&& config );
+
+        ~JsonReporter() override;
+
+        static std::string getDescription();
+
+    public: // StreamingReporterBase
+        void testRunStarting( TestRunInfo const& runInfo ) override;
+        void testRunEnded( TestRunStats const& runStats ) override;
+
+        void testCaseStarting( TestCaseInfo const& tcInfo ) override;
+        void testCaseEnded( TestCaseStats const& tcStats ) override;
+
+        void testCasePartialStarting( TestCaseInfo const& tcInfo,
+                                      uint64_t index ) override;
+        void testCasePartialEnded( TestCaseStats const& tcStats,
+                                   uint64_t index ) override;
+
+        void sectionStarting( SectionInfo const& sectionInfo ) override;
+        void sectionEnded( SectionStats const& sectionStats ) override;
+
+        void assertionStarting( AssertionInfo const& assertionInfo ) override;
+        void assertionEnded( AssertionStats const& assertionStats ) override;
+
+        //void testRunEndedCumulative() override;
+
+        void benchmarkPreparing( StringRef name ) override;
+        void benchmarkStarting( BenchmarkInfo const& ) override;
+        void benchmarkEnded( BenchmarkStats<> const& ) override;
+        void benchmarkFailed( StringRef error ) override;
+
+        void listReporters(
+            std::vector<ReporterDescription> const& descriptions ) override;
+        void listListeners(
+            std::vector<ListenerDescription> const& descriptions ) override;
+        void listTests( std::vector<TestCaseHandle> const& tests ) override;
+        void listTags( std::vector<TagInfo> const& tags ) override;
+
+    private:
+        Timer m_testCaseTimer;
+        enum class Writer {
+            Object,
+            Array
+        };
+
+        JsonArrayWriter& startArray();
+        JsonArrayWriter& startArray( std::string const& key );
+
+        JsonObjectWriter& startObject();
+        JsonObjectWriter& startObject( std::string const& key );
+
+        void endObject();
+        void endArray();
+
+        bool isInside( Writer writer );
+
+        void startListing();
+        void endListing();
+
+        // Invariant:
+        // When m_writers is not empty and its top element is
+        // - Writer::Object, then m_objectWriters is not be empty
+        // - Writer::Array,  then m_arrayWriters shall not be empty
+        std::stack<JsonObjectWriter> m_objectWriters{};
+        std::stack<JsonArrayWriter> m_arrayWriters{};
+        std::stack<Writer> m_writers{};
+
+        bool m_startedListing = false;
+
+        // std::size_t m_sectionDepth = 0;
+        // std::size_t m_sectionStarted = 0;
+    };
+} // namespace Catch
+
+#endif // CATCH_REPORTER_JSON_HPP_INCLUDED
diff --git a/src/catch2/reporters/catch_reporters_all.hpp b/src/catch2/reporters/catch_reporters_all.hpp
index 16f7bd70..5c713fe1 100644
--- a/src/catch2/reporters/catch_reporters_all.hpp
+++ b/src/catch2/reporters/catch_reporters_all.hpp
@@ -28,6 +28,7 @@
 #include <catch2/reporters/catch_reporter_cumulative_base.hpp>
 #include <catch2/reporters/catch_reporter_event_listener.hpp>
 #include <catch2/reporters/catch_reporter_helpers.hpp>
+#include <catch2/reporters/catch_reporter_json.hpp>
 #include <catch2/reporters/catch_reporter_junit.hpp>
 #include <catch2/reporters/catch_reporter_multi.hpp>
 #include <catch2/reporters/catch_reporter_registrars.hpp>
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 74017c38..4c3bad84 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -87,6 +87,7 @@ set(TEST_SOURCES
         ${SELF_TEST_DIR}/IntrospectiveTests/FloatingPoint.tests.cpp
         ${SELF_TEST_DIR}/IntrospectiveTests/GeneratorsImpl.tests.cpp
         ${SELF_TEST_DIR}/IntrospectiveTests/InternalBenchmark.tests.cpp
+        ${SELF_TEST_DIR}/IntrospectiveTests/Json.tests.cpp
         ${SELF_TEST_DIR}/IntrospectiveTests/Parse.tests.cpp
         ${SELF_TEST_DIR}/IntrospectiveTests/PartTracker.tests.cpp
         ${SELF_TEST_DIR}/IntrospectiveTests/RandomNumberGeneration.tests.cpp
@@ -642,7 +643,8 @@ foreach (reporterName # "Automake" - the simple .trs format does not support any
                       "SonarQube"
                       "TAP"
                       # "TeamCity" - does not seem to support test suite-level metadata/comments
-                      "XML")
+                      "XML"
+                      "JSON")
 
     add_test(NAME "Reporters:Filters:${reporterName}"
       COMMAND
@@ -652,6 +654,8 @@ foreach (reporterName # "Automake" - the simple .trs format does not support any
     # Different regex for these two reporters, because the commas end up xml-escaped
     if (reporterName MATCHES "JUnit|XML")
       set(testCaseNameFormat "&quot;CaseInsensitiveLess is case insensitive&quot;")
+    elseif(reporterName MATCHES "JSON")
+      set(testCaseNameFormat "\\\\\"CaseInsensitiveLess is case insensitive\\\\\"")
     else()
       set(testCaseNameFormat "\"CaseInsensitiveLess is case insensitive\"")
     endif()
diff --git a/tests/SelfTest/Baselines/automake.sw.approved.txt b/tests/SelfTest/Baselines/automake.sw.approved.txt
index 6748c0ec..0f029e6d 100644
--- a/tests/SelfTest/Baselines/automake.sw.approved.txt
+++ b/tests/SelfTest/Baselines/automake.sw.approved.txt
@@ -170,6 +170,7 @@ Nor would this
 :test-result: XFAIL Incomplete AssertionHandler
 :test-result: XFAIL Inequality checks that should fail
 :test-result: PASS Inequality checks that should succeed
+:test-result: PASS JsonWriter
 :test-result: PASS Lambdas in assertions
 :test-result: PASS Less-than inequalities with different epsilons
 :test-result: PASS ManuallyRegistered
diff --git a/tests/SelfTest/Baselines/automake.sw.multi.approved.txt b/tests/SelfTest/Baselines/automake.sw.multi.approved.txt
index a8bdcfa1..a3af0658 100644
--- a/tests/SelfTest/Baselines/automake.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/automake.sw.multi.approved.txt
@@ -168,6 +168,7 @@
 :test-result: XFAIL Incomplete AssertionHandler
 :test-result: XFAIL Inequality checks that should fail
 :test-result: PASS Inequality checks that should succeed
+:test-result: PASS JsonWriter
 :test-result: PASS Lambdas in assertions
 :test-result: PASS Less-than inequalities with different epsilons
 :test-result: PASS ManuallyRegistered
diff --git a/tests/SelfTest/Baselines/compact.sw.approved.txt b/tests/SelfTest/Baselines/compact.sw.approved.txt
index dafa08db..e78c989f 100644
--- a/tests/SelfTest/Baselines/compact.sw.approved.txt
+++ b/tests/SelfTest/Baselines/compact.sw.approved.txt
@@ -979,6 +979,83 @@ Condition.tests.cpp:<line number>: passed: data.str_hello != "goodbye" for: "hel
 Condition.tests.cpp:<line number>: passed: data.str_hello != "hell" for: "hello" != "hell"
 Condition.tests.cpp:<line number>: passed: data.str_hello != "hello1" for: "hello" != "hello1"
 Condition.tests.cpp:<line number>: passed: data.str_hello.size() != 6 for: 5 != 6
+Json.tests.cpp:<line number>: passed: stream.str() == "" for: "" == ""
+Json.tests.cpp:<line number>: passed: stream.str() == "{\n}" for: "{
+}"
+==
+"{
+}"
+Json.tests.cpp:<line number>: passed: stream.str(), ContainsSubstring( "\"int\": 1," ) && ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"true\": true," ) && ContainsSubstring( "\"false\": false," ) && ContainsSubstring( "\"string\": \"this is a string\"," ) && ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) for: "{
+  "int": 1,
+  "double": 1.5,
+  "true": true,
+  "false": false,
+  "string": "this is a string",
+  "array": [
+    1,
+    2
+  ]
+}" ( contains: ""int": 1," and contains: ""double": 1.5," and contains: ""true": true," and contains: ""false": false," and contains: ""string": "this is a string"," and contains: ""array": [
+    1,
+    2
+  ]
+}" )
+Json.tests.cpp:<line number>: passed: stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) && ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" ) for: "{
+  "empty_object": {
+  },
+  "fully_object": {
+    "key": 1
+  }
+}" ( contains: ""empty_object": {
+  }," and contains: ""fully_object": {
+    "key": 1
+  }" )
+Json.tests.cpp:<line number>: passed: stream.str() == "[\n]" for: "[
+]"
+==
+"[
+]"
+Json.tests.cpp:<line number>: passed: stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" for: "[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+==
+"[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+Json.tests.cpp:<line number>: passed: stream.str() == "{\n}" for: "{
+}"
+==
+"{
+}"
+Json.tests.cpp:<line number>: passed: stream.str() == "[\n]" for: "[
+]"
+==
+"[
+]"
+Json.tests.cpp:<line number>: passed: stream.str() == "\"custom\"" for: ""custom"" == ""custom""
+Json.tests.cpp:<line number>: passed: stream.str() == "\"\\\"\"" for: ""\""" == ""\"""
 Compilation.tests.cpp:<line number>: passed: []() { return true; }() for: true
 Approx.tests.cpp:<line number>: passed: d <= Approx( 1.24 ) for: 1.23 <= Approx( 1.24 )
 Approx.tests.cpp:<line number>: passed: d <= Approx( 1.23 ) for: 1.23 <= Approx( 1.23 )
@@ -1343,6 +1420,60 @@ Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring( "fa
 
 " ( contains: "fake test name" and contains: "fakeTestTag" ) with 1 message: 'Tested reporter: console'
 Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
+Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring("fakeTag"s) for: "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tags": [
+      {
+        "aliases": [
+          "fakeTag"
+        ],
+        "count": 1
+      }
+    ]" contains: "fakeTag" with 1 message: 'Tested reporter: JSON'
+Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
+Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring("fake reporter"s) for: "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "reporters": [
+      {
+        "name": "fake reporter",
+        "description": "fake description"
+      }
+    ]" contains: "fake reporter" with 1 message: 'Tested reporter: JSON'
+Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
+Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring( "fake test name"s ) && ContainsSubstring( "fakeTestTag"s ) for: "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tests": [
+      {
+        "name": "fake test name",
+        "class-name": "",
+        "tags": [
+          "fakeTestTag"
+        ],
+        "source-location": {
+          "filename": "fake-file.cpp",
+          "line": 123456789
+        }
+      }
+    ]" ( contains: "fake test name" and contains: "fakeTestTag" ) with 1 message: 'Tested reporter: JSON'
+Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
 Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring("fakeTag"s) for: "<?xml version="1.0" encoding="UTF-8"?>
 All available tags:
    1  [fakeTag]
@@ -2544,7 +2675,7 @@ InternalBenchmark.tests.cpp:<line number>: passed: med == 18. for: 18.0 == 18.0
 InternalBenchmark.tests.cpp:<line number>: passed: q3 == 23. for: 23.0 == 23.0
 Misc.tests.cpp:<line number>: passed:
 Misc.tests.cpp:<line number>: passed:
-test cases:  413 |  308 passed |  85 failed | 6 skipped | 14 failed as expected
-assertions: 2230 | 2049 passed | 146 failed | 35 failed as expected
+test cases:  414 |  309 passed |  85 failed | 6 skipped | 14 failed as expected
+assertions: 2246 | 2065 passed | 146 failed | 35 failed as expected
 
 
diff --git a/tests/SelfTest/Baselines/compact.sw.multi.approved.txt b/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
index 36debdb7..8f177e46 100644
--- a/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
@@ -977,6 +977,83 @@ Condition.tests.cpp:<line number>: passed: data.str_hello != "goodbye" for: "hel
 Condition.tests.cpp:<line number>: passed: data.str_hello != "hell" for: "hello" != "hell"
 Condition.tests.cpp:<line number>: passed: data.str_hello != "hello1" for: "hello" != "hello1"
 Condition.tests.cpp:<line number>: passed: data.str_hello.size() != 6 for: 5 != 6
+Json.tests.cpp:<line number>: passed: stream.str() == "" for: "" == ""
+Json.tests.cpp:<line number>: passed: stream.str() == "{\n}" for: "{
+}"
+==
+"{
+}"
+Json.tests.cpp:<line number>: passed: stream.str(), ContainsSubstring( "\"int\": 1," ) && ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"true\": true," ) && ContainsSubstring( "\"false\": false," ) && ContainsSubstring( "\"string\": \"this is a string\"," ) && ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) for: "{
+  "int": 1,
+  "double": 1.5,
+  "true": true,
+  "false": false,
+  "string": "this is a string",
+  "array": [
+    1,
+    2
+  ]
+}" ( contains: ""int": 1," and contains: ""double": 1.5," and contains: ""true": true," and contains: ""false": false," and contains: ""string": "this is a string"," and contains: ""array": [
+    1,
+    2
+  ]
+}" )
+Json.tests.cpp:<line number>: passed: stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) && ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" ) for: "{
+  "empty_object": {
+  },
+  "fully_object": {
+    "key": 1
+  }
+}" ( contains: ""empty_object": {
+  }," and contains: ""fully_object": {
+    "key": 1
+  }" )
+Json.tests.cpp:<line number>: passed: stream.str() == "[\n]" for: "[
+]"
+==
+"[
+]"
+Json.tests.cpp:<line number>: passed: stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" for: "[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+==
+"[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+Json.tests.cpp:<line number>: passed: stream.str() == "{\n}" for: "{
+}"
+==
+"{
+}"
+Json.tests.cpp:<line number>: passed: stream.str() == "[\n]" for: "[
+]"
+==
+"[
+]"
+Json.tests.cpp:<line number>: passed: stream.str() == "\"custom\"" for: ""custom"" == ""custom""
+Json.tests.cpp:<line number>: passed: stream.str() == "\"\\\"\"" for: ""\""" == ""\"""
 Compilation.tests.cpp:<line number>: passed: []() { return true; }() for: true
 Approx.tests.cpp:<line number>: passed: d <= Approx( 1.24 ) for: 1.23 <= Approx( 1.24 )
 Approx.tests.cpp:<line number>: passed: d <= Approx( 1.23 ) for: 1.23 <= Approx( 1.23 )
@@ -1341,6 +1418,60 @@ Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring( "fa
 
 " ( contains: "fake test name" and contains: "fakeTestTag" ) with 1 message: 'Tested reporter: console'
 Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
+Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring("fakeTag"s) for: "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tags": [
+      {
+        "aliases": [
+          "fakeTag"
+        ],
+        "count": 1
+      }
+    ]" contains: "fakeTag" with 1 message: 'Tested reporter: JSON'
+Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
+Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring("fake reporter"s) for: "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "reporters": [
+      {
+        "name": "fake reporter",
+        "description": "fake description"
+      }
+    ]" contains: "fake reporter" with 1 message: 'Tested reporter: JSON'
+Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
+Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring( "fake test name"s ) && ContainsSubstring( "fakeTestTag"s ) for: "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tests": [
+      {
+        "name": "fake test name",
+        "class-name": "",
+        "tags": [
+          "fakeTestTag"
+        ],
+        "source-location": {
+          "filename": "fake-file.cpp",
+          "line": 123456789
+        }
+      }
+    ]" ( contains: "fake test name" and contains: "fakeTestTag" ) with 1 message: 'Tested reporter: JSON'
+Reporters.tests.cpp:<line number>: passed: !(factories.empty()) for: !false
 Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring("fakeTag"s) for: "<?xml version="1.0" encoding="UTF-8"?>
 All available tags:
    1  [fakeTag]
@@ -2533,7 +2664,7 @@ InternalBenchmark.tests.cpp:<line number>: passed: med == 18. for: 18.0 == 18.0
 InternalBenchmark.tests.cpp:<line number>: passed: q3 == 23. for: 23.0 == 23.0
 Misc.tests.cpp:<line number>: passed:
 Misc.tests.cpp:<line number>: passed:
-test cases:  413 |  308 passed |  85 failed | 6 skipped | 14 failed as expected
-assertions: 2230 | 2049 passed | 146 failed | 35 failed as expected
+test cases:  414 |  309 passed |  85 failed | 6 skipped | 14 failed as expected
+assertions: 2246 | 2065 passed | 146 failed | 35 failed as expected
 
 
diff --git a/tests/SelfTest/Baselines/console.std.approved.txt b/tests/SelfTest/Baselines/console.std.approved.txt
index 4ad25ed8..9aa0d038 100644
--- a/tests/SelfTest/Baselines/console.std.approved.txt
+++ b/tests/SelfTest/Baselines/console.std.approved.txt
@@ -1588,6 +1588,6 @@ due to unexpected exception with message:
   Why would you throw a std::string?
 
 ===============================================================================
-test cases:  413 |  322 passed |  70 failed | 7 skipped | 14 failed as expected
-assertions: 2213 | 2049 passed | 129 failed | 35 failed as expected
+test cases:  414 |  323 passed |  70 failed | 7 skipped | 14 failed as expected
+assertions: 2229 | 2065 passed | 129 failed | 35 failed as expected
 
diff --git a/tests/SelfTest/Baselines/console.sw.approved.txt b/tests/SelfTest/Baselines/console.sw.approved.txt
index d56e8c41..71cbbd27 100644
--- a/tests/SelfTest/Baselines/console.sw.approved.txt
+++ b/tests/SelfTest/Baselines/console.sw.approved.txt
@@ -7258,6 +7258,195 @@ Condition.tests.cpp:<line number>: PASSED:
 with expansion:
   5 != 6
 
+-------------------------------------------------------------------------------
+JsonWriter
+  Newly constructed JsonWriter does nothing
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "" )
+with expansion:
+  "" == ""
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeObject will create an empty pair of braces
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "{\n}" )
+with expansion:
+  "{
+  }"
+  ==
+  "{
+  }"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeObject with key will create an object to write the value
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( stream.str(), ContainsSubstring( "\"int\": 1," ) && ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"true\": true," ) && ContainsSubstring( "\"false\": false," ) && ContainsSubstring( "\"string\": \"this is a string\"," ) && ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) )
+with expansion:
+  "{
+    "int": 1,
+    "double": 1.5,
+    "true": true,
+    "false": false,
+    "string": "this is a string",
+    "array": [
+      1,
+      2
+    ]
+  }" ( contains: ""int": 1," and contains: ""double": 1.5," and contains:
+  ""true": true," and contains: ""false": false," and contains: ""string":
+  "this is a string"," and contains: ""array": [
+      1,
+      2
+    ]
+  }" )
+
+-------------------------------------------------------------------------------
+JsonWriter
+  nesting objects
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) && ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" ) )
+with expansion:
+  "{
+    "empty_object": {
+    },
+    "fully_object": {
+      "key": 1
+    }
+  }" ( contains: ""empty_object": {
+    }," and contains: ""fully_object": {
+      "key": 1
+    }" )
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeArray will create an empty pair of braces
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "[\n]" )
+with expansion:
+  "[
+  ]"
+  ==
+  "[
+  ]"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeArray creates array to write the values to
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" )
+with expansion:
+  "[
+    1,
+    1.5,
+    true,
+    false,
+    "this is a string",
+    {
+      "object": 42
+    },
+    [
+      "array",
+      42.5
+    ]
+  ]"
+  ==
+  "[
+    1,
+    1.5,
+    true,
+    false,
+    "this is a string",
+    {
+      "object": 42
+    },
+    [
+      "array",
+      42.5
+    ]
+  ]"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Moved from JsonObjectWriter shall not insert superfluous brace
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "{\n}" )
+with expansion:
+  "{
+  }"
+  ==
+  "{
+  }"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Moved from JsonArrayWriter shall not insert superfluous bracket
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "[\n]" )
+with expansion:
+  "[
+  ]"
+  ==
+  "[
+  ]"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Custom class shall be quoted
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "\"custom\"" )
+with expansion:
+  ""custom"" == ""custom""
+
+-------------------------------------------------------------------------------
+JsonWriter
+  String with a quote shall be espaced
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "\"\\\"\"" )
+with expansion:
+  ""\""" == ""\"""
+
 -------------------------------------------------------------------------------
 Lambdas in assertions
 -------------------------------------------------------------------------------
@@ -9756,6 +9945,129 @@ Reporter's write listings to provided stream
 Reporters.tests.cpp:<line number>
 ...............................................................................
 
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( factories.empty() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+  JSON reporter lists tags
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( listingString, ContainsSubstring("fakeTag"s) )
+with expansion:
+  "{
+    "version": 1,
+    "metadata": {
+      "name": "",
+      "rng-seed": 1234,
+      "catch2-version": "<version>"
+    },
+    "listings": {
+      "tags": [
+        {
+          "aliases": [
+            "fakeTag"
+          ],
+          "count": 1
+        }
+      ]" contains: "fakeTag"
+with message:
+  Tested reporter: JSON
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( factories.empty() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+  JSON reporter lists reporters
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( listingString, ContainsSubstring("fake reporter"s) )
+with expansion:
+  "{
+    "version": 1,
+    "metadata": {
+      "name": "",
+      "rng-seed": 1234,
+      "catch2-version": "<version>"
+    },
+    "listings": {
+      "reporters": [
+        {
+          "name": "fake reporter",
+          "description": "fake description"
+        }
+      ]" contains: "fake reporter"
+with message:
+  Tested reporter: JSON
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( factories.empty() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+  JSON reporter lists tests
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( listingString, ContainsSubstring( "fake test name"s ) && ContainsSubstring( "fakeTestTag"s ) )
+with expansion:
+  "{
+    "version": 1,
+    "metadata": {
+      "name": "",
+      "rng-seed": 1234,
+      "catch2-version": "<version>"
+    },
+    "listings": {
+      "tests": [
+        {
+          "name": "fake test name",
+          "class-name": "",
+          "tags": [
+            "fakeTestTag"
+          ],
+          "source-location": {
+            "filename": "fake-file.cpp",
+            "line": 123456789
+          }
+        }
+      ]" ( contains: "fake test name" and contains: "fakeTestTag" )
+with message:
+  Tested reporter: JSON
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
 Reporters.tests.cpp:<line number>: PASSED:
   REQUIRE_FALSE( factories.empty() )
 with expansion:
@@ -18283,6 +18595,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  413 |  308 passed |  85 failed | 6 skipped | 14 failed as expected
-assertions: 2230 | 2049 passed | 146 failed | 35 failed as expected
+test cases:  414 |  309 passed |  85 failed | 6 skipped | 14 failed as expected
+assertions: 2246 | 2065 passed | 146 failed | 35 failed as expected
 
diff --git a/tests/SelfTest/Baselines/console.sw.multi.approved.txt b/tests/SelfTest/Baselines/console.sw.multi.approved.txt
index be965932..ccb27333 100644
--- a/tests/SelfTest/Baselines/console.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/console.sw.multi.approved.txt
@@ -7256,6 +7256,195 @@ Condition.tests.cpp:<line number>: PASSED:
 with expansion:
   5 != 6
 
+-------------------------------------------------------------------------------
+JsonWriter
+  Newly constructed JsonWriter does nothing
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "" )
+with expansion:
+  "" == ""
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeObject will create an empty pair of braces
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "{\n}" )
+with expansion:
+  "{
+  }"
+  ==
+  "{
+  }"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeObject with key will create an object to write the value
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( stream.str(), ContainsSubstring( "\"int\": 1," ) && ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"true\": true," ) && ContainsSubstring( "\"false\": false," ) && ContainsSubstring( "\"string\": \"this is a string\"," ) && ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) )
+with expansion:
+  "{
+    "int": 1,
+    "double": 1.5,
+    "true": true,
+    "false": false,
+    "string": "this is a string",
+    "array": [
+      1,
+      2
+    ]
+  }" ( contains: ""int": 1," and contains: ""double": 1.5," and contains:
+  ""true": true," and contains: ""false": false," and contains: ""string":
+  "this is a string"," and contains: ""array": [
+      1,
+      2
+    ]
+  }" )
+
+-------------------------------------------------------------------------------
+JsonWriter
+  nesting objects
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) && ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" ) )
+with expansion:
+  "{
+    "empty_object": {
+    },
+    "fully_object": {
+      "key": 1
+    }
+  }" ( contains: ""empty_object": {
+    }," and contains: ""fully_object": {
+      "key": 1
+    }" )
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeArray will create an empty pair of braces
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "[\n]" )
+with expansion:
+  "[
+  ]"
+  ==
+  "[
+  ]"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Calling writeArray creates array to write the values to
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" )
+with expansion:
+  "[
+    1,
+    1.5,
+    true,
+    false,
+    "this is a string",
+    {
+      "object": 42
+    },
+    [
+      "array",
+      42.5
+    ]
+  ]"
+  ==
+  "[
+    1,
+    1.5,
+    true,
+    false,
+    "this is a string",
+    {
+      "object": 42
+    },
+    [
+      "array",
+      42.5
+    ]
+  ]"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Moved from JsonObjectWriter shall not insert superfluous brace
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "{\n}" )
+with expansion:
+  "{
+  }"
+  ==
+  "{
+  }"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Moved from JsonArrayWriter shall not insert superfluous bracket
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "[\n]" )
+with expansion:
+  "[
+  ]"
+  ==
+  "[
+  ]"
+
+-------------------------------------------------------------------------------
+JsonWriter
+  Custom class shall be quoted
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "\"custom\"" )
+with expansion:
+  ""custom"" == ""custom""
+
+-------------------------------------------------------------------------------
+JsonWriter
+  String with a quote shall be espaced
+-------------------------------------------------------------------------------
+Json.tests.cpp:<line number>
+...............................................................................
+
+Json.tests.cpp:<line number>: PASSED:
+  REQUIRE( stream.str() == "\"\\\"\"" )
+with expansion:
+  ""\""" == ""\"""
+
 -------------------------------------------------------------------------------
 Lambdas in assertions
 -------------------------------------------------------------------------------
@@ -9754,6 +9943,129 @@ Reporter's write listings to provided stream
 Reporters.tests.cpp:<line number>
 ...............................................................................
 
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( factories.empty() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+  JSON reporter lists tags
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( listingString, ContainsSubstring("fakeTag"s) )
+with expansion:
+  "{
+    "version": 1,
+    "metadata": {
+      "name": "",
+      "rng-seed": 1234,
+      "catch2-version": "<version>"
+    },
+    "listings": {
+      "tags": [
+        {
+          "aliases": [
+            "fakeTag"
+          ],
+          "count": 1
+        }
+      ]" contains: "fakeTag"
+with message:
+  Tested reporter: JSON
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( factories.empty() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+  JSON reporter lists reporters
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( listingString, ContainsSubstring("fake reporter"s) )
+with expansion:
+  "{
+    "version": 1,
+    "metadata": {
+      "name": "",
+      "rng-seed": 1234,
+      "catch2-version": "<version>"
+    },
+    "listings": {
+      "reporters": [
+        {
+          "name": "fake reporter",
+          "description": "fake description"
+        }
+      ]" contains: "fake reporter"
+with message:
+  Tested reporter: JSON
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( factories.empty() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+  JSON reporter lists tests
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
+Reporters.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( listingString, ContainsSubstring( "fake test name"s ) && ContainsSubstring( "fakeTestTag"s ) )
+with expansion:
+  "{
+    "version": 1,
+    "metadata": {
+      "name": "",
+      "rng-seed": 1234,
+      "catch2-version": "<version>"
+    },
+    "listings": {
+      "tests": [
+        {
+          "name": "fake test name",
+          "class-name": "",
+          "tags": [
+            "fakeTestTag"
+          ],
+          "source-location": {
+            "filename": "fake-file.cpp",
+            "line": 123456789
+          }
+        }
+      ]" ( contains: "fake test name" and contains: "fakeTestTag" )
+with message:
+  Tested reporter: JSON
+
+-------------------------------------------------------------------------------
+Reporter's write listings to provided stream
+-------------------------------------------------------------------------------
+Reporters.tests.cpp:<line number>
+...............................................................................
+
 Reporters.tests.cpp:<line number>: PASSED:
   REQUIRE_FALSE( factories.empty() )
 with expansion:
@@ -18272,6 +18584,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  413 |  308 passed |  85 failed | 6 skipped | 14 failed as expected
-assertions: 2230 | 2049 passed | 146 failed | 35 failed as expected
+test cases:  414 |  309 passed |  85 failed | 6 skipped | 14 failed as expected
+assertions: 2246 | 2065 passed | 146 failed | 35 failed as expected
 
diff --git a/tests/SelfTest/Baselines/junit.sw.approved.txt b/tests/SelfTest/Baselines/junit.sw.approved.txt
index 3b6c8fa0..beb235b5 100644
--- a/tests/SelfTest/Baselines/junit.sw.approved.txt
+++ b/tests/SelfTest/Baselines/junit.sw.approved.txt
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuitesloose text artifact
 >
-  <testsuite name="<exe-name>" errors="17" failures="129" skipped="12" tests="2242" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="129" skipped="12" tests="2258" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="random-seed" value="1"/>
       <property name="filters" value="&quot;*&quot; ~[!nonportable] ~[!benchmark] ~[approvals]"/>
@@ -853,6 +853,16 @@ at Condition.tests.cpp:<line number>
       </failure>
     </testcase>
     <testcase classname="<exe-name>.global" name="Inequality checks that should succeed" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Newly constructed JsonWriter does nothing" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeObject will create an empty pair of braces" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeObject with key will create an object to write the value" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/nesting objects" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeArray will create an empty pair of braces" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeArray creates array to write the values to" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Moved from JsonObjectWriter shall not insert superfluous brace" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Moved from JsonArrayWriter shall not insert superfluous bracket" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Custom class shall be quoted" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/String with a quote shall be espaced" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Lambdas in assertions" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Less-than inequalities with different epsilons" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="ManuallyRegistered" time="{duration}" status="run"/>
@@ -1190,6 +1200,9 @@ at Matchers.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/console reporter lists tags" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/console reporter lists reporters" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/console reporter lists tests" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JSON reporter lists tags" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JSON reporter lists reporters" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JSON reporter lists tests" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JUnit reporter lists tags" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JUnit reporter lists reporters" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JUnit reporter lists tests" time="{duration}" status="run"/>
diff --git a/tests/SelfTest/Baselines/junit.sw.multi.approved.txt b/tests/SelfTest/Baselines/junit.sw.multi.approved.txt
index 48b8acc8..a5dd3063 100644
--- a/tests/SelfTest/Baselines/junit.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/junit.sw.multi.approved.txt
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuites>
-  <testsuite name="<exe-name>" errors="17" failures="129" skipped="12" tests="2242" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="129" skipped="12" tests="2258" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="random-seed" value="1"/>
       <property name="filters" value="&quot;*&quot; ~[!nonportable] ~[!benchmark] ~[approvals]"/>
@@ -852,6 +852,16 @@ at Condition.tests.cpp:<line number>
       </failure>
     </testcase>
     <testcase classname="<exe-name>.global" name="Inequality checks that should succeed" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Newly constructed JsonWriter does nothing" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeObject will create an empty pair of braces" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeObject with key will create an object to write the value" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/nesting objects" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeArray will create an empty pair of braces" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Calling writeArray creates array to write the values to" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Moved from JsonObjectWriter shall not insert superfluous brace" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Moved from JsonArrayWriter shall not insert superfluous bracket" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/Custom class shall be quoted" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="JsonWriter/String with a quote shall be espaced" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Lambdas in assertions" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Less-than inequalities with different epsilons" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="ManuallyRegistered" time="{duration}" status="run"/>
@@ -1189,6 +1199,9 @@ at Matchers.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/console reporter lists tags" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/console reporter lists reporters" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/console reporter lists tests" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JSON reporter lists tags" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JSON reporter lists reporters" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JSON reporter lists tests" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JUnit reporter lists tags" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JUnit reporter lists reporters" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Reporter's write listings to provided stream/JUnit reporter lists tests" time="{duration}" status="run"/>
diff --git a/tests/SelfTest/Baselines/sonarqube.sw.approved.txt b/tests/SelfTest/Baselines/sonarqube.sw.approved.txt
index b634d27e..eaef6357 100644
--- a/tests/SelfTest/Baselines/sonarqube.sw.approved.txt
+++ b/tests/SelfTest/Baselines/sonarqube.sw.approved.txt
@@ -130,6 +130,18 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="warmup" duration="{duration}"/>
     <testCase name="weighted_average_quantile" duration="{duration}"/>
   </file>
+  <file path="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp">
+    <testCase name="JsonWriter/Newly constructed JsonWriter does nothing" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeObject will create an empty pair of braces" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeObject with key will create an object to write the value" duration="{duration}"/>
+    <testCase name="JsonWriter/nesting objects" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeArray will create an empty pair of braces" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeArray creates array to write the values to" duration="{duration}"/>
+    <testCase name="JsonWriter/Moved from JsonObjectWriter shall not insert superfluous brace" duration="{duration}"/>
+    <testCase name="JsonWriter/Moved from JsonArrayWriter shall not insert superfluous bracket" duration="{duration}"/>
+    <testCase name="JsonWriter/Custom class shall be quoted" duration="{duration}"/>
+    <testCase name="JsonWriter/String with a quote shall be espaced" duration="{duration}"/>
+  </file>
   <file path="tests/<exe-name>/IntrospectiveTests/Parse.tests.cpp">
     <testCase name="Parse uints/proper inputs" duration="{duration}"/>
     <testCase name="Parse uints/Bad inputs" duration="{duration}"/>
@@ -178,6 +190,9 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="Reporter's write listings to provided stream/console reporter lists tags" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/console reporter lists reporters" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/console reporter lists tests" duration="{duration}"/>
+    <testCase name="Reporter's write listings to provided stream/JSON reporter lists tags" duration="{duration}"/>
+    <testCase name="Reporter's write listings to provided stream/JSON reporter lists reporters" duration="{duration}"/>
+    <testCase name="Reporter's write listings to provided stream/JSON reporter lists tests" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/JUnit reporter lists tags" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/JUnit reporter lists reporters" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/JUnit reporter lists tests" duration="{duration}"/>
diff --git a/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt b/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt
index 33c9c208..bb23a995 100644
--- a/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt
@@ -129,6 +129,18 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="warmup" duration="{duration}"/>
     <testCase name="weighted_average_quantile" duration="{duration}"/>
   </file>
+  <file path="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp">
+    <testCase name="JsonWriter/Newly constructed JsonWriter does nothing" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeObject will create an empty pair of braces" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeObject with key will create an object to write the value" duration="{duration}"/>
+    <testCase name="JsonWriter/nesting objects" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeArray will create an empty pair of braces" duration="{duration}"/>
+    <testCase name="JsonWriter/Calling writeArray creates array to write the values to" duration="{duration}"/>
+    <testCase name="JsonWriter/Moved from JsonObjectWriter shall not insert superfluous brace" duration="{duration}"/>
+    <testCase name="JsonWriter/Moved from JsonArrayWriter shall not insert superfluous bracket" duration="{duration}"/>
+    <testCase name="JsonWriter/Custom class shall be quoted" duration="{duration}"/>
+    <testCase name="JsonWriter/String with a quote shall be espaced" duration="{duration}"/>
+  </file>
   <file path="tests/<exe-name>/IntrospectiveTests/Parse.tests.cpp">
     <testCase name="Parse uints/proper inputs" duration="{duration}"/>
     <testCase name="Parse uints/Bad inputs" duration="{duration}"/>
@@ -177,6 +189,9 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="Reporter's write listings to provided stream/console reporter lists tags" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/console reporter lists reporters" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/console reporter lists tests" duration="{duration}"/>
+    <testCase name="Reporter's write listings to provided stream/JSON reporter lists tags" duration="{duration}"/>
+    <testCase name="Reporter's write listings to provided stream/JSON reporter lists reporters" duration="{duration}"/>
+    <testCase name="Reporter's write listings to provided stream/JSON reporter lists tests" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/JUnit reporter lists tags" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/JUnit reporter lists reporters" duration="{duration}"/>
     <testCase name="Reporter's write listings to provided stream/JUnit reporter lists tests" duration="{duration}"/>
diff --git a/tests/SelfTest/Baselines/tap.sw.approved.txt b/tests/SelfTest/Baselines/tap.sw.approved.txt
index 26a7fa94..e32e6589 100644
--- a/tests/SelfTest/Baselines/tap.sw.approved.txt
+++ b/tests/SelfTest/Baselines/tap.sw.approved.txt
@@ -1866,6 +1866,26 @@ ok {test-number} - data.str_hello != "hell" for: "hello" != "hell"
 ok {test-number} - data.str_hello != "hello1" for: "hello" != "hello1"
 # Inequality checks that should succeed
 ok {test-number} - data.str_hello.size() != 6 for: 5 != 6
+# JsonWriter
+ok {test-number} - stream.str() == "" for: "" == ""
+# JsonWriter
+ok {test-number} - stream.str() == "{\n}" for: "{ }" == "{ }"
+# JsonWriter
+ok {test-number} - stream.str(), ContainsSubstring( "\"int\": 1," ) && ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"true\": true," ) && ContainsSubstring( "\"false\": false," ) && ContainsSubstring( "\"string\": \"this is a string\"," ) && ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) for: "{   "int": 1,   "double": 1.5,   "true": true,   "false": false,   "string": "this is a string",   "array": [     1,     2   ] }" ( contains: ""int": 1," and contains: ""double": 1.5," and contains: ""true": true," and contains: ""false": false," and contains: ""string": "this is a string"," and contains: ""array": [     1,     2   ] }" )
+# JsonWriter
+ok {test-number} - stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) && ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" ) for: "{   "empty_object": {   },   "fully_object": {     "key": 1   } }" ( contains: ""empty_object": {   }," and contains: ""fully_object": {     "key": 1   }" )
+# JsonWriter
+ok {test-number} - stream.str() == "[\n]" for: "[ ]" == "[ ]"
+# JsonWriter
+ok {test-number} - stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" for: "[   1,   1.5,   true,   false,   "this is a string",   {     "object": 42   },   [     "array",     42.5   ] ]" == "[   1,   1.5,   true,   false,   "this is a string",   {     "object": 42   },   [     "array",     42.5   ] ]"
+# JsonWriter
+ok {test-number} - stream.str() == "{\n}" for: "{ }" == "{ }"
+# JsonWriter
+ok {test-number} - stream.str() == "[\n]" for: "[ ]" == "[ ]"
+# JsonWriter
+ok {test-number} - stream.str() == "\"custom\"" for: ""custom"" == ""custom""
+# JsonWriter
+ok {test-number} - stream.str() == "\"\\\"\"" for: ""\""" == ""\"""
 # Lambdas in assertions
 ok {test-number} - []() { return true; }() for: true
 # Less-than inequalities with different epsilons
@@ -2459,6 +2479,18 @@ ok {test-number} - listingString, ContainsSubstring( "fake test name"s ) && Cont
 # Reporter's write listings to provided stream
 ok {test-number} - !(factories.empty()) for: !false
 # Reporter's write listings to provided stream
+ok {test-number} - listingString, ContainsSubstring("fakeTag"s) for: "{   "version": 1,   "metadata": {     "name": "",     "rng-seed": 1234,     "catch2-version": "<version>"   },   "listings": {     "tags": [       {         "aliases": [           "fakeTag"         ],         "count": 1       }     ]" contains: "fakeTag" with 1 message: 'Tested reporter: JSON'
+# Reporter's write listings to provided stream
+ok {test-number} - !(factories.empty()) for: !false
+# Reporter's write listings to provided stream
+ok {test-number} - listingString, ContainsSubstring("fake reporter"s) for: "{   "version": 1,   "metadata": {     "name": "",     "rng-seed": 1234,     "catch2-version": "<version>"   },   "listings": {     "reporters": [       {         "name": "fake reporter",         "description": "fake description"       }     ]" contains: "fake reporter" with 1 message: 'Tested reporter: JSON'
+# Reporter's write listings to provided stream
+ok {test-number} - !(factories.empty()) for: !false
+# Reporter's write listings to provided stream
+ok {test-number} - listingString, ContainsSubstring( "fake test name"s ) && ContainsSubstring( "fakeTestTag"s ) for: "{   "version": 1,   "metadata": {     "name": "",     "rng-seed": 1234,     "catch2-version": "<version>"   },   "listings": {     "tests": [       {         "name": "fake test name",         "class-name": "",         "tags": [           "fakeTestTag"         ],         "source-location": {           "filename": "fake-file.cpp",           "line": 123456789         }       }     ]" ( contains: "fake test name" and contains: "fakeTestTag" ) with 1 message: 'Tested reporter: JSON'
+# Reporter's write listings to provided stream
+ok {test-number} - !(factories.empty()) for: !false
+# Reporter's write listings to provided stream
 ok {test-number} - listingString, ContainsSubstring("fakeTag"s) for: "<?xml version="1.0" encoding="UTF-8"?> All available tags:    1  [fakeTag] 1 tag  " contains: "fakeTag" with 1 message: 'Tested reporter: JUnit'
 # Reporter's write listings to provided stream
 ok {test-number} - !(factories.empty()) for: !false
@@ -4489,5 +4521,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..2242
+1..2258
 
diff --git a/tests/SelfTest/Baselines/tap.sw.multi.approved.txt b/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
index b9a075c1..5d3f0560 100644
--- a/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
@@ -1864,6 +1864,26 @@ ok {test-number} - data.str_hello != "hell" for: "hello" != "hell"
 ok {test-number} - data.str_hello != "hello1" for: "hello" != "hello1"
 # Inequality checks that should succeed
 ok {test-number} - data.str_hello.size() != 6 for: 5 != 6
+# JsonWriter
+ok {test-number} - stream.str() == "" for: "" == ""
+# JsonWriter
+ok {test-number} - stream.str() == "{\n}" for: "{ }" == "{ }"
+# JsonWriter
+ok {test-number} - stream.str(), ContainsSubstring( "\"int\": 1," ) && ContainsSubstring( "\"double\": 1.5," ) && ContainsSubstring( "\"true\": true," ) && ContainsSubstring( "\"false\": false," ) && ContainsSubstring( "\"string\": \"this is a string\"," ) && ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) for: "{   "int": 1,   "double": 1.5,   "true": true,   "false": false,   "string": "this is a string",   "array": [     1,     2   ] }" ( contains: ""int": 1," and contains: ""double": 1.5," and contains: ""true": true," and contains: ""false": false," and contains: ""string": "this is a string"," and contains: ""array": [     1,     2   ] }" )
+# JsonWriter
+ok {test-number} - stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) && ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" ) for: "{   "empty_object": {   },   "fully_object": {     "key": 1   } }" ( contains: ""empty_object": {   }," and contains: ""fully_object": {     "key": 1   }" )
+# JsonWriter
+ok {test-number} - stream.str() == "[\n]" for: "[ ]" == "[ ]"
+# JsonWriter
+ok {test-number} - stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" for: "[   1,   1.5,   true,   false,   "this is a string",   {     "object": 42   },   [     "array",     42.5   ] ]" == "[   1,   1.5,   true,   false,   "this is a string",   {     "object": 42   },   [     "array",     42.5   ] ]"
+# JsonWriter
+ok {test-number} - stream.str() == "{\n}" for: "{ }" == "{ }"
+# JsonWriter
+ok {test-number} - stream.str() == "[\n]" for: "[ ]" == "[ ]"
+# JsonWriter
+ok {test-number} - stream.str() == "\"custom\"" for: ""custom"" == ""custom""
+# JsonWriter
+ok {test-number} - stream.str() == "\"\\\"\"" for: ""\""" == ""\"""
 # Lambdas in assertions
 ok {test-number} - []() { return true; }() for: true
 # Less-than inequalities with different epsilons
@@ -2457,6 +2477,18 @@ ok {test-number} - listingString, ContainsSubstring( "fake test name"s ) && Cont
 # Reporter's write listings to provided stream
 ok {test-number} - !(factories.empty()) for: !false
 # Reporter's write listings to provided stream
+ok {test-number} - listingString, ContainsSubstring("fakeTag"s) for: "{   "version": 1,   "metadata": {     "name": "",     "rng-seed": 1234,     "catch2-version": "<version>"   },   "listings": {     "tags": [       {         "aliases": [           "fakeTag"         ],         "count": 1       }     ]" contains: "fakeTag" with 1 message: 'Tested reporter: JSON'
+# Reporter's write listings to provided stream
+ok {test-number} - !(factories.empty()) for: !false
+# Reporter's write listings to provided stream
+ok {test-number} - listingString, ContainsSubstring("fake reporter"s) for: "{   "version": 1,   "metadata": {     "name": "",     "rng-seed": 1234,     "catch2-version": "<version>"   },   "listings": {     "reporters": [       {         "name": "fake reporter",         "description": "fake description"       }     ]" contains: "fake reporter" with 1 message: 'Tested reporter: JSON'
+# Reporter's write listings to provided stream
+ok {test-number} - !(factories.empty()) for: !false
+# Reporter's write listings to provided stream
+ok {test-number} - listingString, ContainsSubstring( "fake test name"s ) && ContainsSubstring( "fakeTestTag"s ) for: "{   "version": 1,   "metadata": {     "name": "",     "rng-seed": 1234,     "catch2-version": "<version>"   },   "listings": {     "tests": [       {         "name": "fake test name",         "class-name": "",         "tags": [           "fakeTestTag"         ],         "source-location": {           "filename": "fake-file.cpp",           "line": 123456789         }       }     ]" ( contains: "fake test name" and contains: "fakeTestTag" ) with 1 message: 'Tested reporter: JSON'
+# Reporter's write listings to provided stream
+ok {test-number} - !(factories.empty()) for: !false
+# Reporter's write listings to provided stream
 ok {test-number} - listingString, ContainsSubstring("fakeTag"s) for: "<?xml version="1.0" encoding="UTF-8"?> All available tags:    1  [fakeTag] 1 tag  " contains: "fakeTag" with 1 message: 'Tested reporter: JUnit'
 # Reporter's write listings to provided stream
 ok {test-number} - !(factories.empty()) for: !false
@@ -4478,5 +4510,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..2242
+1..2258
 
diff --git a/tests/SelfTest/Baselines/teamcity.sw.approved.txt b/tests/SelfTest/Baselines/teamcity.sw.approved.txt
index 4293464d..35ff74ac 100644
--- a/tests/SelfTest/Baselines/teamcity.sw.approved.txt
+++ b/tests/SelfTest/Baselines/teamcity.sw.approved.txt
@@ -420,6 +420,8 @@
 ##teamcity[testFinished name='Inequality checks that should fail' duration="{duration}"]
 ##teamcity[testStarted name='Inequality checks that should succeed']
 ##teamcity[testFinished name='Inequality checks that should succeed' duration="{duration}"]
+##teamcity[testStarted name='JsonWriter']
+##teamcity[testFinished name='JsonWriter' duration="{duration}"]
 ##teamcity[testStarted name='Lambdas in assertions']
 ##teamcity[testFinished name='Lambdas in assertions' duration="{duration}"]
 ##teamcity[testStarted name='Less-than inequalities with different epsilons']
diff --git a/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt b/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt
index b68d8bdb..d559c1fe 100644
--- a/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/teamcity.sw.multi.approved.txt
@@ -420,6 +420,8 @@
 ##teamcity[testFinished name='Inequality checks that should fail' duration="{duration}"]
 ##teamcity[testStarted name='Inequality checks that should succeed']
 ##teamcity[testFinished name='Inequality checks that should succeed' duration="{duration}"]
+##teamcity[testStarted name='JsonWriter']
+##teamcity[testFinished name='JsonWriter' duration="{duration}"]
 ##teamcity[testStarted name='Lambdas in assertions']
 ##teamcity[testFinished name='Lambdas in assertions' duration="{duration}"]
 ##teamcity[testStarted name='Less-than inequalities with different epsilons']
diff --git a/tests/SelfTest/Baselines/xml.sw.approved.txt b/tests/SelfTest/Baselines/xml.sw.approved.txt
index 28ed5c86..c6059ea8 100644
--- a/tests/SelfTest/Baselines/xml.sw.approved.txt
+++ b/tests/SelfTest/Baselines/xml.sw.approved.txt
@@ -8779,6 +8779,186 @@ C
     </Expression>
     <OverallResult success="true" skips="0"/>
   </TestCase>
+  <TestCase name="JsonWriter" tags="[JSON][JsonWriter]" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+    <Section name="Newly constructed JsonWriter does nothing" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == ""
+        </Original>
+        <Expanded>
+          "" == ""
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeObject will create an empty pair of braces" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "{\n}"
+        </Original>
+        <Expanded>
+          "{
+}"
+==
+"{
+}"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeObject with key will create an object to write the value" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str(), ContainsSubstring( "\"int\": 1," ) &amp;&amp; ContainsSubstring( "\"double\": 1.5," ) &amp;&amp; ContainsSubstring( "\"true\": true," ) &amp;&amp; ContainsSubstring( "\"false\": false," ) &amp;&amp; ContainsSubstring( "\"string\": \"this is a string\"," ) &amp;&amp; ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" )
+        </Original>
+        <Expanded>
+          "{
+  "int": 1,
+  "double": 1.5,
+  "true": true,
+  "false": false,
+  "string": "this is a string",
+  "array": [
+    1,
+    2
+  ]
+}" ( contains: ""int": 1," and contains: ""double": 1.5," and contains: ""true": true," and contains: ""false": false," and contains: ""string": "this is a string"," and contains: ""array": [
+    1,
+    2
+  ]
+}" )
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="nesting objects" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) &amp;&amp; ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" )
+        </Original>
+        <Expanded>
+          "{
+  "empty_object": {
+  },
+  "fully_object": {
+    "key": 1
+  }
+}" ( contains: ""empty_object": {
+  }," and contains: ""fully_object": {
+    "key": 1
+  }" )
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeArray will create an empty pair of braces" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "[\n]"
+        </Original>
+        <Expanded>
+          "[
+]"
+==
+"[
+]"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeArray creates array to write the values to" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]"
+        </Original>
+        <Expanded>
+          "[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+==
+"[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Moved from JsonObjectWriter shall not insert superfluous brace" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "{\n}"
+        </Original>
+        <Expanded>
+          "{
+}"
+==
+"{
+}"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Moved from JsonArrayWriter shall not insert superfluous bracket" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "[\n]"
+        </Original>
+        <Expanded>
+          "[
+]"
+==
+"[
+]"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Custom class shall be quoted" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "\"custom\""
+        </Original>
+        <Expanded>
+          ""custom"" == ""custom""
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="String with a quote shall be espaced" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "\"\\\"\""
+        </Original>
+        <Expanded>
+          ""\""" == ""\"""
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <OverallResult success="true" skips="0"/>
+  </TestCase>
   <TestCase name="Lambdas in assertions" filename="tests/<exe-name>/UsageTests/Compilation.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Compilation.tests.cpp" >
       <Original>
@@ -11695,6 +11875,120 @@ C
         !false
       </Expanded>
     </Expression>
+    <Section name="JSON reporter lists tags" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        Tested reporter: JSON
+      </Info>
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        <Original>
+          listingString, ContainsSubstring("fakeTag"s)
+        </Original>
+        <Expanded>
+          "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tags": [
+      {
+        "aliases": [
+          "fakeTag"
+        ],
+        "count": 1
+      }
+    ]" contains: "fakeTag"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Expression success="true" type="REQUIRE_FALSE" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Original>
+        !(factories.empty())
+      </Original>
+      <Expanded>
+        !false
+      </Expanded>
+    </Expression>
+    <Section name="JSON reporter lists reporters" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        Tested reporter: JSON
+      </Info>
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        <Original>
+          listingString, ContainsSubstring("fake reporter"s)
+        </Original>
+        <Expanded>
+          "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "reporters": [
+      {
+        "name": "fake reporter",
+        "description": "fake description"
+      }
+    ]" contains: "fake reporter"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Expression success="true" type="REQUIRE_FALSE" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Original>
+        !(factories.empty())
+      </Original>
+      <Expanded>
+        !false
+      </Expanded>
+    </Expression>
+    <Section name="JSON reporter lists tests" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        Tested reporter: JSON
+      </Info>
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        <Original>
+          listingString, ContainsSubstring( "fake test name"s ) &amp;&amp; ContainsSubstring( "fakeTestTag"s )
+        </Original>
+        <Expanded>
+          "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tests": [
+      {
+        "name": "fake test name",
+        "class-name": "",
+        "tags": [
+          "fakeTestTag"
+        ],
+        "source-location": {
+          "filename": "fake-file.cpp",
+          "line": 123456789
+        }
+      }
+    ]" ( contains: "fake test name" and contains: "fakeTestTag" )
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Expression success="true" type="REQUIRE_FALSE" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Original>
+        !(factories.empty())
+      </Original>
+      <Expanded>
+        !false
+      </Expanded>
+    </Expression>
     <Section name="JUnit reporter lists tags" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
       <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
         Tested reporter: JUnit
@@ -21268,6 +21562,6 @@ b1!
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
-  <OverallResults successes="2049" failures="146" expectedFailures="35" skips="12"/>
-  <OverallResultsCases successes="308" failures="85" expectedFailures="14" skips="6"/>
+  <OverallResults successes="2065" failures="146" expectedFailures="35" skips="12"/>
+  <OverallResultsCases successes="309" failures="85" expectedFailures="14" skips="6"/>
 </Catch2TestRun>
diff --git a/tests/SelfTest/Baselines/xml.sw.multi.approved.txt b/tests/SelfTest/Baselines/xml.sw.multi.approved.txt
index 0f3210db..23df72f3 100644
--- a/tests/SelfTest/Baselines/xml.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/xml.sw.multi.approved.txt
@@ -8779,6 +8779,186 @@ C
     </Expression>
     <OverallResult success="true" skips="0"/>
   </TestCase>
+  <TestCase name="JsonWriter" tags="[JSON][JsonWriter]" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+    <Section name="Newly constructed JsonWriter does nothing" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == ""
+        </Original>
+        <Expanded>
+          "" == ""
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeObject will create an empty pair of braces" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "{\n}"
+        </Original>
+        <Expanded>
+          "{
+}"
+==
+"{
+}"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeObject with key will create an object to write the value" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str(), ContainsSubstring( "\"int\": 1," ) &amp;&amp; ContainsSubstring( "\"double\": 1.5," ) &amp;&amp; ContainsSubstring( "\"true\": true," ) &amp;&amp; ContainsSubstring( "\"false\": false," ) &amp;&amp; ContainsSubstring( "\"string\": \"this is a string\"," ) &amp;&amp; ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" )
+        </Original>
+        <Expanded>
+          "{
+  "int": 1,
+  "double": 1.5,
+  "true": true,
+  "false": false,
+  "string": "this is a string",
+  "array": [
+    1,
+    2
+  ]
+}" ( contains: ""int": 1," and contains: ""double": 1.5," and contains: ""true": true," and contains: ""false": false," and contains: ""string": "this is a string"," and contains: ""array": [
+    1,
+    2
+  ]
+}" )
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="nesting objects" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str(), ContainsSubstring( "\"empty_object\": {\n  }," ) &amp;&amp; ContainsSubstring( "\"fully_object\": {\n    \"key\": 1\n  }" )
+        </Original>
+        <Expanded>
+          "{
+  "empty_object": {
+  },
+  "fully_object": {
+    "key": 1
+  }
+}" ( contains: ""empty_object": {
+  }," and contains: ""fully_object": {
+    "key": 1
+  }" )
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeArray will create an empty pair of braces" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "[\n]"
+        </Original>
+        <Expanded>
+          "[
+]"
+==
+"[
+]"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Calling writeArray creates array to write the values to" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]"
+        </Original>
+        <Expanded>
+          "[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+==
+"[
+  1,
+  1.5,
+  true,
+  false,
+  "this is a string",
+  {
+    "object": 42
+  },
+  [
+    "array",
+    42.5
+  ]
+]"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Moved from JsonObjectWriter shall not insert superfluous brace" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "{\n}"
+        </Original>
+        <Expanded>
+          "{
+}"
+==
+"{
+}"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Moved from JsonArrayWriter shall not insert superfluous bracket" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "[\n]"
+        </Original>
+        <Expanded>
+          "[
+]"
+==
+"[
+]"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="Custom class shall be quoted" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "\"custom\""
+        </Original>
+        <Expanded>
+          ""custom"" == ""custom""
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="String with a quote shall be espaced" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/Json.tests.cpp" >
+        <Original>
+          stream.str() == "\"\\\"\""
+        </Original>
+        <Expanded>
+          ""\""" == ""\"""
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <OverallResult success="true" skips="0"/>
+  </TestCase>
   <TestCase name="Lambdas in assertions" filename="tests/<exe-name>/UsageTests/Compilation.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Compilation.tests.cpp" >
       <Original>
@@ -11695,6 +11875,120 @@ C
         !false
       </Expanded>
     </Expression>
+    <Section name="JSON reporter lists tags" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        Tested reporter: JSON
+      </Info>
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        <Original>
+          listingString, ContainsSubstring("fakeTag"s)
+        </Original>
+        <Expanded>
+          "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tags": [
+      {
+        "aliases": [
+          "fakeTag"
+        ],
+        "count": 1
+      }
+    ]" contains: "fakeTag"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Expression success="true" type="REQUIRE_FALSE" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Original>
+        !(factories.empty())
+      </Original>
+      <Expanded>
+        !false
+      </Expanded>
+    </Expression>
+    <Section name="JSON reporter lists reporters" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        Tested reporter: JSON
+      </Info>
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        <Original>
+          listingString, ContainsSubstring("fake reporter"s)
+        </Original>
+        <Expanded>
+          "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "reporters": [
+      {
+        "name": "fake reporter",
+        "description": "fake description"
+      }
+    ]" contains: "fake reporter"
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Expression success="true" type="REQUIRE_FALSE" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Original>
+        !(factories.empty())
+      </Original>
+      <Expanded>
+        !false
+      </Expanded>
+    </Expression>
+    <Section name="JSON reporter lists tests" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        Tested reporter: JSON
+      </Info>
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+        <Original>
+          listingString, ContainsSubstring( "fake test name"s ) &amp;&amp; ContainsSubstring( "fakeTestTag"s )
+        </Original>
+        <Expanded>
+          "{
+  "version": 1,
+  "metadata": {
+    "name": "",
+    "rng-seed": 1234,
+    "catch2-version": "<version>"
+  },
+  "listings": {
+    "tests": [
+      {
+        "name": "fake test name",
+        "class-name": "",
+        "tags": [
+          "fakeTestTag"
+        ],
+        "source-location": {
+          "filename": "fake-file.cpp",
+          "line": 123456789
+        }
+      }
+    ]" ( contains: "fake test name" and contains: "fakeTestTag" )
+        </Expanded>
+      </Expression>
+      <OverallResults successes="1" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Expression success="true" type="REQUIRE_FALSE" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
+      <Original>
+        !(factories.empty())
+      </Original>
+      <Expanded>
+        !false
+      </Expanded>
+    </Expression>
     <Section name="JUnit reporter lists tags" filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
       <Info filename="tests/<exe-name>/IntrospectiveTests/Reporters.tests.cpp" >
         Tested reporter: JUnit
@@ -21267,6 +21561,6 @@ b1!
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
-  <OverallResults successes="2049" failures="146" expectedFailures="35" skips="12"/>
-  <OverallResultsCases successes="308" failures="85" expectedFailures="14" skips="6"/>
+  <OverallResults successes="2065" failures="146" expectedFailures="35" skips="12"/>
+  <OverallResultsCases successes="309" failures="85" expectedFailures="14" skips="6"/>
 </Catch2TestRun>
diff --git a/tests/SelfTest/IntrospectiveTests/Json.tests.cpp b/tests/SelfTest/IntrospectiveTests/Json.tests.cpp
new file mode 100644
index 00000000..9ade94ee
--- /dev/null
+++ b/tests/SelfTest/IntrospectiveTests/Json.tests.cpp
@@ -0,0 +1,116 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/internal/catch_jsonwriter.hpp>
+#include <catch2/matchers/catch_matchers_string.hpp>
+
+#include <sstream>
+
+namespace {
+    struct Custom {};
+    std::ostream& operator<<( std::ostream& os, Custom const& ) {
+        return os << "custom";
+    }
+} // namespace
+
+TEST_CASE( "JsonWriter", "[JSON][JsonWriter]" ) {
+
+    std::stringstream stream{};
+    SECTION( "Newly constructed JsonWriter does nothing" ) {
+        Catch::JsonValueWriter writer{ stream };
+        REQUIRE( stream.str() == "" );
+    }
+
+    SECTION( "Calling writeObject will create an empty pair of braces" ) {
+        { auto writer = Catch::JsonValueWriter{ stream }.writeObject(); }
+        REQUIRE( stream.str() == "{\n}" );
+    }
+
+    SECTION( "Calling writeObject with key will create an object to write the "
+             "value" ) {
+        using Catch::Matchers::ContainsSubstring;
+        {
+            auto writer = Catch::JsonValueWriter{ stream }.writeObject();
+            writer.write( "int" ).write( 1 );
+            writer.write( "double" ).write( 1.5 );
+            writer.write( "true" ).write( true );
+            writer.write( "false" ).write( false );
+            writer.write( "string" ).write( "this is a string" );
+            writer.write( "array" ).writeArray().write( 1 ).write( 2 );
+        }
+        REQUIRE_THAT(
+            stream.str(),
+            ContainsSubstring( "\"int\": 1," ) &&
+                ContainsSubstring( "\"double\": 1.5," ) &&
+                ContainsSubstring( "\"true\": true," ) &&
+                ContainsSubstring( "\"false\": false," ) &&
+                ContainsSubstring( "\"string\": \"this is a string\"," ) &&
+                ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) );
+    }
+
+    SECTION( "nesting objects" ) {
+        using Catch::Matchers::ContainsSubstring;
+        {
+            auto writer = Catch::JsonValueWriter{ stream }.writeObject();
+            writer.write( "empty_object" ).writeObject();
+            writer.write( "fully_object" )
+                .writeObject()
+                .write( "key" )
+                .write( 1 );
+        }
+        REQUIRE_THAT( stream.str(),
+                      ContainsSubstring( "\"empty_object\": {\n  }," ) &&
+                          ContainsSubstring(
+                              "\"fully_object\": {\n    \"key\": 1\n  }" ) );
+    }
+
+    SECTION( "Calling writeArray will create an empty pair of braces" ) {
+        { auto writer = Catch::JsonValueWriter{ stream }.writeArray(); }
+        REQUIRE( stream.str() == "[\n]" );
+    }
+
+    SECTION( "Calling writeArray creates array to write the values to" ) {
+        {
+            auto writer = Catch::JsonValueWriter{ stream }.writeArray();
+            writer.write( 1 );
+            writer.write( 1.5 );
+            writer.write( true );
+            writer.write( false );
+            writer.write( "this is a string" );
+            writer.writeObject().write( "object" ).write( 42 );
+            writer.writeArray().write( "array" ).write( 42.5 );
+        }
+        REQUIRE( stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" );
+    }
+
+    SECTION(
+        "Moved from JsonObjectWriter shall not insert superfluous brace" ) {
+        {
+            auto writer = Catch::JsonObjectWriter{ stream };
+            auto another_writer = std::move( writer );
+        }
+        REQUIRE( stream.str() == "{\n}" );
+    }
+    SECTION(
+        "Moved from JsonArrayWriter shall not insert superfluous bracket" ) {
+        {
+            auto writer = Catch::JsonArrayWriter{ stream };
+            auto another_writer = std::move( writer );
+        }
+        REQUIRE( stream.str() == "[\n]" );
+    }
+    SECTION( "Custom class shall be quoted" ) {
+        Catch::JsonValueWriter{ stream }.write( Custom{} );
+        REQUIRE( stream.str() == "\"custom\"" );
+    }
+    SECTION( "String with a quote shall be espaced" ) {
+        Catch::JsonValueWriter{ stream }.write( "\"" );
+        REQUIRE( stream.str() == "\"\\\"\"" );
+    }
+}
diff --git a/tests/SelfTest/IntrospectiveTests/Reporters.tests.cpp b/tests/SelfTest/IntrospectiveTests/Reporters.tests.cpp
index 1568c951..e5a65bda 100644
--- a/tests/SelfTest/IntrospectiveTests/Reporters.tests.cpp
+++ b/tests/SelfTest/IntrospectiveTests/Reporters.tests.cpp
@@ -109,7 +109,9 @@ TEST_CASE( "Reporter's write listings to provided stream", "[reporters]" ) {
         auto sstream = Catch::Detail::make_unique<StringIStream>();
         auto& sstreamRef = *sstream.get();
 
-        Catch::Config config( Catch::ConfigData{} );
+        Catch::ConfigData cfg_data;
+        cfg_data.rngSeed = 1234;
+        Catch::Config config( cfg_data );
         auto reporter = factory.second->create( Catch::ReporterConfig{
             &config, CATCH_MOVE( sstream ), Catch::ColourMode::None, {} } );