• When a user makes a pytest call, this hook runs. We create the SnapshotSystem, and find all the tests that are planning to run.

  • selfie/python/pytest-selfie/pytest_selfie/plugin.py

    Lines 68 to 78 in f1325e8

    	@pytest.hookimpl
    	def pytest_collection_modifyitems(
    	session: pytest.Session, config: pytest.Config, items: List[pytest.Item]
    	) -> None:
    	settings = SelfieSettingsAPI(config)
    	system = PytestSnapshotSystem(settings)
    	session.selfie_system = system # type: ignore
    	_initSelfieSystem(system)
    	for item in items:
    	(file, _, testname) = item.reportinfo()
    	system.planning_to_run(TypedPath.of_file(os.path.abspath(file)), testname)

• For each test that runs, this method gets called.

  • selfie/python/pytest-selfie/pytest_selfie/plugin.py

    Lines 88 to 96 in f1325e8

    	@pytest.hookimpl(hookwrapper=True)
    	def pytest_runtest_protocol(item: pytest.Item, nextitem: Optional[pytest.Item]):
    	(file, _, testname) = item.reportinfo()
    	testfile = TypedPath.of_file(os.path.abspath(file))
    	system: PytestSnapshotSystem = item.session.selfie_system # type: ignore
    	system.test_start(testfile, testname)
    	yield
    	system.test_finish(testfile, testname)

  • we notify the system that a test is starting
  • the test runs at the yield
  • we notify the system that a test has finished
• Within that yield call, this function gets called when a test has something to report

  • selfie/python/pytest-selfie/pytest_selfie/plugin.py

    Lines 99 to 107 in f1325e8

    	@pytest.hookimpl
    	def pytest_runtest_makereport(call: pytest.CallInfo[None], item: pytest.Item):
    	if call.excinfo is not None and call.when in (
    	"call",
    	"teardown",
    	):
    	system: PytestSnapshotSystem = item.session.selfie_system # type: ignore
    	(file, _, testname) = item.reportinfo()
    	system.test_failed(TypedPath.of_file(os.path.abspath(file)), testname)

  • if a test fails during the call or teardown phases, we notify the system so that GC won't run
• And at the very end we call this to mark that everything is done and we can write everything to disk

  • selfie/python/pytest-selfie/pytest_selfie/plugin.py

    Lines 81 to 85 in f1325e8

    	@pytest.hookimpl
    	def pytest_sessionfinish(session: pytest.Session, exitstatus):
    	system: PytestSnapshotSystem = session.selfie_system # type: ignore
    	system.finished_all_tests()
    	_clearSelfieSystem(system)

  • An important asterisk is that SnapshotFiles are read / written to disk as we go, they don't wait until the end.

If you look in example-pytest-selfie, you'll see three tests which exercise the subsystems you have built to-date:

• @hssahota2 https://github.com/diffplug/selfie/blob/main/python/example-pytest-selfie/tests/simple_comment_removal_test.py
• @SDelgado-21 https://github.com/diffplug/selfie/blob/main/python/example-pytest-selfie/tests/simple_inline_test.py
• @Trickybrain https://github.com/diffplug/selfie/blob/main/python/example-pytest-selfie/tests/simple_ondisk_test.py

If you run them, you'll see that the SnapshotSystem is all wired up to them, but with some NotImplementedError along the way.

If you have something in-progress, go ahead and finish that up. Otherwise, try to get your subsystem to work in this context.