Implement warning for unmatched test specs

docs/command-line.md

@@ -212,14 +212,22 @@ This option transforms tabs and newline characters into ```\t``` and ```\n``` re
 ## Warnings
 <pre>-w, --warn &lt;warning name></pre>
 
-Enables reporting of suspicious test runs. There is currently only one
-available warning.
+You can think of Catch2's warnings as the equivalent of `-Werror` (`/WX`)
+flag for C++ compilers. It turns some suspicious occurences, like a section
+without assertions, into errors. Because these might be intended, warnings
+are not enabled by default, but user can opt in.
+
+There are currently two warnings implemented:
 
 ```
     NoAssertions        // Fail test case / leaf section if no assertions
                         // (e.g. `REQUIRE`) is encountered.
+    UnmatchedTestSpec   // Fail test run if any of the CLI test specs did
+                        // not match any tests.
 ```
 
+> `UnmatchedTestSpec` was introduced in Catch2 X.Y.Z.
+
 
 <a id="reporting-timings"></a>
 ## Reporting timings

docs/release-notes.md

@@ -173,6 +173,7 @@ new design.
   * When deferred tu runtime, it behaves like `CHECK`, and not like `REQUIRE`.
 * You can have multiple tests with the same name, as long as other parts of the test identity differ (#1915, #1999, #2175)
   * Test identity includes test's name, test's tags and and test's class name if applicable.
+* Added new warning, `UnmatchedTestSpec`, to error on test specs with no matching tests
 
 
 ### Fixes

src/catch2/catch_config.cpp

@@ -70,6 +70,9 @@ namespace Catch {
     bool Config::warnAboutMissingAssertions() const {
         return !!( m_data.warnings & WarnAbout::NoAssertions );
     }
+    bool Config::warnAboutUnmatchedTestSpecs() const {
+        return !!( m_data.warnings & WarnAbout::UnmatchedTestSpec );
+    }
     bool Config::zeroTestsCountAsSuccess() const       { return m_data.allowZeroTests; }
     ShowDurations Config::showDurations() const        { return m_data.showDurations; }
     double Config::minDuration() const                 { return m_data.minDuration; }

src/catch2/catch_config.hpp

@@ -98,6 +98,7 @@ namespace Catch {
         StringRef name() const override;
         bool includeSuccessfulResults() const override;
         bool warnAboutMissingAssertions() const override;
+        bool warnAboutUnmatchedTestSpecs() const override;
         bool zeroTestsCountAsSuccess() const override;
         ShowDurations showDurations() const override;
         double minDuration() const override;

src/catch2/catch_session.cpp

@@ -96,20 +96,26 @@ namespace Catch {
 
                 for (auto const& match : m_matches) {
                     if (match.tests.empty()) {
+                        m_unmatchedTestSpecs = true;
                         m_reporter->noMatchingTestCases( match.name );
-                        totals.error = -1;
                     }
                 }
 
                 return totals;
             }
 
+            bool hadUnmatchedTestSpecs() const {
+                return m_unmatchedTestSpecs;
+            }
+
+
         private:
             IStreamingReporter* m_reporter;
             Config const* m_config;
             RunContext m_context;
             std::set<TestCaseHandle const*> m_tests;
             TestSpec::Matches m_matches;
+            bool m_unmatchedTestSpecs = false;
         };
 
         void applyFilenamesAsTags() {
@@ -301,6 +307,11 @@ namespace Catch {
             TestGroup tests { CATCH_MOVE(reporter), m_config.get() };
             auto const totals = tests.execute();
 
+            if ( tests.hadUnmatchedTestSpecs()
+                && m_config->warnAboutUnmatchedTestSpecs() ) {
+                return 3;
+            }
+
             if ( totals.testCases.total() == 0
                 && !m_config->zeroTestsCountAsSuccess() ) {
                 return 2;

src/catch2/interfaces/catch_interfaces_config.hpp

@@ -26,7 +26,10 @@ namespace Catch {
 
     struct WarnAbout { enum What {
         Nothing = 0x00,
+        //! A test case or leaf section did not run any assertions
         NoAssertions = 0x01,
+        //! A command line test spec matched no test cases
+        UnmatchedTestSpec = 0x02,
     }; };
 
     enum class ShowDurations {
@@ -63,6 +66,7 @@ namespace Catch {
         virtual bool includeSuccessfulResults() const = 0;
         virtual bool shouldDebugBreak() const = 0;
         virtual bool warnAboutMissingAssertions() const = 0;
+        virtual bool warnAboutUnmatchedTestSpecs() const = 0;
         virtual bool zeroTestsCountAsSuccess() const = 0;
         virtual int abortAfter() const = 0;
         virtual bool showInvisibles() const = 0;

src/catch2/internal/catch_commandline.cpp

@@ -27,6 +27,9 @@ namespace Catch {
             if ( warning == "NoAssertions" ) {
                 config.warnings = WarnAbout::NoAssertions;
                 return ParserResult::ok( ParseResultType::Matched );
+            } else if ( warning == "UnmatchedTestSpec" ) {
+                config.warnings = WarnAbout::UnmatchedTestSpec;
+                return ParserResult::ok( ParseResultType::Matched );
             }
 
             return ParserResult ::runtimeError(

tests/CMakeLists.txt

@@ -229,6 +229,23 @@ add_test(NAME TestSpecs::OverrideFailureWithNoMatchedTests
   COMMAND $<TARGET_FILE:SelfTest> "___nonexistent_test___" --allow-running-no-tests
 )
 
+add_test(NAME Warnings::UnmatchedTestSpecIsAccepted
+  COMMAND $<TARGET_FILE:SelfTest> Tracker --warn UnmatchedTestSpec
+)
+set_tests_properties(Warnings::UnmatchedTestSpecIsAccepted
+  PROPERTIES
+    FAIL_REGULAR_EXPRESSION "Unrecognised warning option: "
+)
+
+add_test(NAME TestSpecs::WarnUnmatchedTestSpecFailsWithUnmatchedTestSpec
+  COMMAND
+    $<TARGET_FILE:SelfTest> Tracker, "___nonexistent_test___" --warn UnmatchedTestSpec
+)
+set_tests_properties(TestSpecs::WarnUnmatchedTestSpecFailsWithUnmatchedTestSpec
+  PROPERTIES
+    WILL_FAIL ON
+)
+
 add_test(NAME UnmatchedOutputFilter COMMAND $<TARGET_FILE:SelfTest> [this-tag-does-not-exist])
 set_tests_properties(UnmatchedOutputFilter
   PROPERTIES