Add option to warn when no tests ran

Closes #1158

include/internal/catch_commandline.cpp

@@ -20,9 +20,19 @@ namespace Catch {
         using namespace clara;
 
         auto const setWarning = [&]( std::string const& warning ) {
-                if( warning != "NoAssertions" )
+                auto warningSet = [&]() {
+                    if( warning == "NoAssertions" )
+                        return WarnAbout::NoAssertions;
+
+                    if ( warning == "NoTests" )
+                        return WarnAbout::NoTests;
+
+                    return WarnAbout::Nothing;
+                }();
+
+                if (warningSet == WarnAbout::Nothing)
                     return ParserResult::runtimeError( "Unrecognised warning: '" + warning + "'" );
-                config.warnings = static_cast<WarnAbout::What>( config.warnings | WarnAbout::NoAssertions );
+                config.warnings = static_cast<WarnAbout::What>( config.warnings | warningSet );
                 return ParserResult::ok( ParseResultType::Matched );
             };
         auto const loadTestNamesFromFile = [&]( std::string const& filename ) {

include/internal/catch_config.cpp

@@ -35,6 +35,7 @@ namespace Catch {
     std::string Config::getProcessName() const { return m_data.processName; }
 
     std::vector<std::string> const& Config::getReporterNames() const { return m_data.reporterNames; }
+    std::vector<std::string> const& Config::getTestsOrTags() const { return m_data.testsOrTags; }
     std::vector<std::string> const& Config::getSectionsToRun() const { return m_data.sectionsToRun; }
 
     TestSpec const& Config::testSpec() const { return m_testSpec; }
@@ -46,7 +47,8 @@ namespace Catch {
     std::ostream& Config::stream() const               { return m_stream->stream(); }
     std::string Config::name() const                   { return m_data.name.empty() ? m_data.processName : m_data.name; }
     bool Config::includeSuccessfulResults() const      { return m_data.showSuccessfulTests; }
-    bool Config::warnAboutMissingAssertions() const    { return m_data.warnings & WarnAbout::NoAssertions; }
+    bool Config::warnAboutMissingAssertions() const    { return !!(m_data.warnings & WarnAbout::NoAssertions); }
+    bool Config::warnAboutNoTests() const              { return !!(m_data.warnings & WarnAbout::NoTests); }
     ShowDurations::OrNot Config::showDurations() const { return m_data.showDurations; }
     RunTests::InWhatOrder Config::runOrder() const     { return m_data.runOrder; }
     unsigned int Config::rngSeed() const               { return m_data.rngSeed; }

include/internal/catch_config.hpp

@@ -78,6 +78,7 @@ namespace Catch {
         std::string getProcessName() const;
 
         std::vector<std::string> const& getReporterNames() const;
+        std::vector<std::string> const& getTestsOrTags() const;
         std::vector<std::string> const& getSectionsToRun() const override;
 
         virtual TestSpec const& testSpec() const override;
@@ -90,6 +91,7 @@ namespace Catch {
         std::string name() const override;
         bool includeSuccessfulResults() const override;
         bool warnAboutMissingAssertions() const override;
+        bool warnAboutNoTests() const override;
         ShowDurations::OrNot showDurations() const override;
         RunTests::InWhatOrder runOrder() const override;
         unsigned int rngSeed() const override;

include/internal/catch_interfaces_config.h

@@ -25,7 +25,8 @@ namespace Catch {
 
     struct WarnAbout { enum What {
         Nothing = 0x00,
-        NoAssertions = 0x01
+        NoAssertions = 0x01,
+        NoTests = 0x02
     }; };
 
     struct ShowDurations { enum OrNot {
@@ -62,6 +63,7 @@ namespace Catch {
         virtual bool includeSuccessfulResults() const = 0;
         virtual bool shouldDebugBreak() const = 0;
         virtual bool warnAboutMissingAssertions() const = 0;
+        virtual bool warnAboutNoTests() const = 0;
         virtual int abortAfter() const = 0;
         virtual bool showInvisibles() const = 0;
         virtual ShowDurations::OrNot showDurations() const = 0;

include/internal/catch_session.cpp

@@ -18,6 +18,7 @@
 #include "catch_random_number_generator.h"
 #include "catch_startup_exception_registry.h"
 #include "catch_text.h"
+#include "catch_stream.h"
 
 #include <cstdlib>
 #include <iomanip>
@@ -80,6 +81,20 @@ namespace Catch {
                     context.reporter().skipTest(testCase);
             }
 
+            if (config->warnAboutNoTests() && totals.testCases.total() == 0) {
+                ReusableStringStream testConfig;
+
+                bool first = true;
+                for (const auto& input : config->getTestsOrTags()) {
+                    if (!first) { testConfig << ' '; }
+                    first = false;
+                    testConfig << input;
+                }
+
+                context.reporter().noMatchingTestCases(testConfig.str());
+                totals.error = -1;
+            }
+
             context.testGroupEnded(config->name(), totals, 1, 1);
             return totals;
         }
@@ -259,10 +274,11 @@ namespace Catch {
             if( Option<std::size_t> listed = list( config() ) )
                 return static_cast<int>( *listed );
 
+            auto totals = runTests( m_config );
             // Note that on unices only the lower 8 bits are usually used, clamping
             // the return value to 255 prevents false negative when some multiple
             // of 256 tests has failed
-            return (std::min)( MaxExitCode, static_cast<int>( runTests( m_config ).assertions.failed ) );
+            return (std::min)( { MaxExitCode, totals.error, static_cast<int>( totals.assertions.failed ) } );
         }
         catch( std::exception& ex ) {
             Catch::cerr() << ex.what() << std::endl;

include/internal/catch_totals.h

@@ -32,7 +32,7 @@ namespace Catch {
 
         Totals delta( Totals const& prevTotals ) const;
 
-
+        int error = 0;
         Counts assertions;
         Counts testCases;
     };