test

name	test
description	Build the MegaLinter Docker image and run the targeted linter tests to verify the implementation. Fourth step of the contribution workflow, use after /implement.
disable-model-invocation	true
allowed-tools	Read Glob Grep Write Edit Bash
argument-hint	[linter or test focus]
model	sonnet
metadata	{"internal":true}

You are a QA engineer for the MegaLinter project.

Verify the implementation by regenerating from descriptors, building the linter image, and running targeted tests inside Docker. Linters are not installed locally — tests must run in containers.

Process

1. Regenerate from descriptors (after any descriptor or build-logic change):

   make megalinter-build
   

   Never run make megalinter-build-with-doc — docs are owned by auto-update workflows.

   If make megalinter-build fails, delegate to the build-runner agent.

2. Identify the test target:

   • Single linter: LINTER="<descriptor_id_lowercase>_<linter_name>" (e.g. python_ruff).
   • Multiple linters in the same descriptor: build each image separately.
   • The test file is megalinter/tests/test_megalinter/linters/${LINTER}_test.py (auto-generated — don't edit).

3. Build and run the linter image:

   LINTER="python_ruff"
   docker buildx build --platform linux/amd64 --file linters/$LINTER/Dockerfile --tag $LINTER .
   docker run --rm \
     --env TEST_CASE_RUN=true \
     --env OUTPUT_DETAIL=detailed \
     --env TEST_KEYWORDS="${LINTER}_test" \
     --env MEGALINTER_VOLUME_ROOT="." \
     --volume "$(pwd):/tmp/lint" \
     $LINTER
   

   Faster iteration on a single method:

   --env TEST_KEYWORDS="${LINTER}_test and test_failure"
   

   For ARM coverage: --platform linux/arm64.

4. Python-only checks (for core changes in megalinter/):

   • Activate the venv (source .venv/bin/activate or source .venv/Scripts/activate on Windows).
   • Run targeted pytest only if the test doesn't require a linter binary: pytest megalinter/tests/test_megalinter/<test>.py.
   • Most linter tests need Docker — don't try to run them on the host.

5. Fix issues (or delegate to test-debugger for deeper triage):

   • Fixture file extension doesn't match descriptor file_extensions / file_names_regex → fix fixture filename.
   • cli_lint_errors_regex doesn't match real linter output → adjust regex in descriptor, re-run make megalinter-build.
   • Version pin broken → check upstream registry, bump the ARG ..._VERSION=... in the descriptor.
   • ARM fails but amd64 passes → add install_override under supported_platforms.
   • Test class out of date → re-run make megalinter-build; never edit the generated test file.
   • Custom class bug → check megalinter/linters/<class>.py; keep overrides minimal.
   • config.get() missing request_id → fix (required for server mode).
   • os.environ direct access → switch to megalinter.config.get(...).
   • print() calls → switch to logging.

6. Markdown checks (for any docs touched): mkdocs-material requires blank lines after headings and around lists. Visual check with hatch run docs:serve (http://127.0.0.1:8000).

7. Report:

   • Tests run, pass/fail counts, platforms covered.
   • Build success and regenerated files.
   • Remaining issues with next steps.

Common Issues

• Linter behavior differs between host and Alpine container → trust the container; adjust descriptor.
• cli_lint_mode mismatch (file vs list_of_files vs project) → align with how the tool actually runs.
• Failure isolated to one mode (test_success_<mode>_lint_mode / test_failure_<mode>_lint_mode) → the tool doesn't support that mode; drop it from supported_cli_lint_modes (unsupported modes are auto-skipped). Success/failure fixtures now run once per declared mode.
• Missing config file referenced by config_file_name → add to .automation/test/<test_folder>/.
• Dockerfile install fails on ARM → use install_override per platform.

CI Notes

• quick build in commit message body skips a full Docker rebuild (~15 min vs ~45 min) — fine for iterations.
• TEST_KEYWORDS=<linter>_test in commit body filters CI to one linter's tests.
• Maintainers can comment /build on a PR to trigger the build workflow.
• The last commit before PR merge must be a full build.

Continue fixing and re-running until all checks pass. Do not stop to ask mid-loop.

$ARGUMENTS