catch2/docs/reporter-events.md

Reporter events

Contents
Test running events
Benchmarking events
Listings events
Miscellaneous events

Reporter events are one of the customization points for user code. They are used by reporters to customize Catch2's output, and by event listeners to perform in-process actions under some conditions.

There are currently 21 reporter events in Catch2, split between 4 distinct event groups:

• test running events (10 events)
• benchmarking (4 events)
• listings (3 events)
• miscellaneous (4 events)

Test running events

Test running events are always paired so that for each fooStarting event, there is a fooEnded event. This means that the 10 test running events consist of 5 pairs of events:

• testRunStarting and testRunEnded,
• testCaseStarting and testCaseEnded,
• testCasePartialStarting and testCasePartialEnded,
• sectionStarting and sectionEnded,
• assertionStarting and assertionEnded

testRun events

void testRunStarting( TestRunInfo const& testRunInfo );
void testRunEnded( TestRunStats const& testRunStats );

The testRun events bookend the entire test run. testRunStarting is emitted before the first test case is executed, and testRunEnded is emitted after all the test cases have been executed.

testCase events

void testCaseStarting( TestCaseInfo const& testInfo );
void testCaseEnded( TestCaseStats const& testCaseStats );

The testCase events bookend one full run of a specific test case. Individual runs through a test case, e.g. due to SECTIONs or GENERATEs, are handled by a different event.

testCasePartial events

Introduced in Catch2 X.Y.Z

void testCasePartialStarting( TestCaseInfo const& testInfo, uint64_t partNumber );
void testCasePartialEnded(TestCaseStats const& testCaseStats, uint64_t partNumber );

testCasePartial events bookend one partial run of a specific test case. This means that for any given test case, these events can be emitted multiple times, e.g. due to multiple leaf sections.

In regards to nesting with testCase events, testCasePartialStarting will never be emitted before the corresponding testCaseStarting, and testCasePartialEnded will always be emitted before the corresponding testCaseEnded.

section events

void sectionStarting( SectionInfo const& sectionInfo );
void sectionEnded( SectionStats const& sectionStats );

section events are emitted only for active SECTIONs, that is, sections that are entered. Sections that are skipped in this test case run-through do not cause events to be emitted.

Note that test cases always contain one implicit section. The event for this section is emitted after the corresponding testCasePartialStarting event.

assertion events

void assertionStarting( AssertionInfo const& assertionInfo );
void assertionEnded( AssertionStats const& assertionStats );

assertionStarting is called after the expression is captured, but before the assertion expression is evaluated. This might seem like a minor distinction, but what it means is that if you have assertion like REQUIRE( a + b == c + d ), then what happens is that a + b and c + d are evaluated before assertionStarting is emitted, while the == is evaluated after the event.

Benchmarking events

Introduced in Catch2 2.9.0.

void benchmarkPreparing( StringRef name ) override;
void benchmarkStarting( BenchmarkInfo const& benchmarkInfo ) override;
void benchmarkEnded( BenchmarkStats<> const& benchmarkStats ) override;
void benchmarkFailed( StringRef error ) override;

Due to the benchmark lifecycle being bit more complicated, the benchmarking events have their own category, even though they could be seen as parallel to the assertion* events. You should expect running a benchmark to generate at least 2 of the events above.

To understand the explanation below, you should read the benchmarking documentation first.

• benchmarkPreparing event is sent after the environmental probe finishes, but before the user code is first estimated.
• benchmarkStarting event is sent after the user code is estimated, but has not been benchmarked yet.
• benchmarkEnded event is sent after the user code has been benchmarked, and contains the benchmarking results.
• benchmarkFailed event is sent if either the estimation or the benchmarking itself fails.

Listings events

Introduced in Catch2 X.Y.Z.

Listings events are events that correspond to the test binary being invoked with --list-foo flag.

There are currently 3 listing events, one for reporters, one for tests, and one for tags. Note that they are not exclusive to each other.

void listReporters( std::vector<ReporterDescription> const& descriptions );
void listTests( std::vector<TestCaseHandle> const& tests );
void listTags( std::vector<TagInfo> const& tagInfos );

Miscellaneous events

void reportInvalidArguments( StringRef unmatchedSpec );
void fatalErrorEncountered( StringRef error );
void noMatchingTestCases( StringRef unmatchedSpec );

These are one-off events that do not neatly fit into other categories.

reportInvalidArguments is sent for each test specification command line argument that wasn't parsed into a valid spec.

fatalErrorEncountered is sent when Catch2's POSIX signal handling or Windows SE handler is called into with a fatal signal/exception.

noMatchingTestCases is sent for each user provided test specification that did not match any registered tests.

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