TAP Output

mu::tiny can emit Test Anything Protocol (TAP) version 13 output via TapOutputPlugin. TAP is a simple line-based format that many CI systems, test harnesses, and tools such as prove can consume directly.

Activating TAP Output

Via command-line flag

Pass -ptap when running your test executable:

./my_tests -ptap

TAP output is written to stdout. Normal console output is suppressed.

Via plugin in main()

TapOutputPlugin is installed automatically when using CommandLineRunner::run_all_tests. If you use a custom runner you can install it manually:

#include "mu/tiny/test/CommandLineRunner.hpp"
#include "mu/tiny/test/Registry.hpp"
#include "mu/tiny/test/TapOutputPlugin.hpp"

int main(int argc, char** argv)
{
    mu::tiny::test::TapOutputPlugin tap;
    mu::tiny::test::Registry::get_current_registry()->install_plugin(&tap);
    return mu::tiny::test::CommandLineRunner::run_all_tests(argc, argv);
}

With the plugin installed, -ptap on the command line enables TAP output. Without the flag, the console output is unchanged.

Output Format

The output follows TAP version 13:

TAP version 13
1..3
ok 1 - Widget.ReturnsInitialValue
not ok 2 - Widget.CanBeSet
  ---
  message: "widget.test.cpp:25: expected <42> but was <0>"
  severity: fail
  at:
    file: widget.test.cpp
    line: 25
  ...
ok 3 - Widget.SkippedTest # SKIP SKIPPED_TEST

Key points:

• The version line TAP version 13 always appears first.

• The plan line 1..N follows immediately, stating the total test count.

• Each test line is ok or not ok, numbered sequentially across all groups.

• Test identifiers use the form <Group>.<Test>.

• Failing tests include a YAML diagnostic block (between --- and ...) with message, severity, and at (file and line).

• severity is fail for assertion failures and comment for unexpected exceptions.

• Skipped (SKIPPED_TEST) and dynamically skipped (SKIP_TEST) tests use the # SKIP <reason> directive.

CI Integration

GitHub Actions

Run the test binary with -ptap and pipe output to a TAP consumer. The tap-summary action, or Perl’s built-in prove, both work:

- name: Run tests (TAP)
  run: ./build/defaults/tests/my_tests -ptap | prove --stdin

- name: Run tests (TAP)
  run: ./build/defaults/tests/my_tests -ptap > results.tap

- name: Validate TAP
  run: prove results.tap

Command line with prove

./my_tests -ptap | prove --stdin