fix: deduplicate must-gather on shared fixture failures

[myakove]

Problem

pytest_exception_interact fires for every test method that encounters an error. When a class-scoped fixture (like prepared_plan) fails during setup, ALL test methods in the class get a setup ERROR. Each ERROR triggers a separate run_must_gather() call — e.g., 6 tests = 6 identical must-gathers for the same root cause.

Observed behavior

When running TestPlanArchivePvcCleanup against an RHV provider with an inactive NFS storage domain, prepared_plan (class-scoped) failed once during VM cloning. All 6 test methods received setup ERRORs, and run_must_gather() was called 6 times — collecting identical cluster state each time.

Root cause

pytest_exception_interact in conftest.py has no deduplication logic. It doesn't check whether the same fixture error already triggered must-gather for a sibling test in the same class.

# conftest.py — current code (no dedup)
def pytest_exception_interact(node, call, report):
    if is_dry_run(node.session.config):
        return

    if not node.session.config.getoption("skip_data_collector"):
        _data_collector_path = Path(
            f"{node.session.config.getoption('data_collector_path')}/{sanitize_test_name_for_path(node.name)}"
        )
        plan = None
        if hasattr(node, "cls") and node.cls and hasattr(node.cls, "plan_resource"):
            plan_obj = node.cls.plan_resource
            if plan_obj:
                plan = {"name": plan_obj.name, "namespace": plan_obj.namespace}

        run_must_gather(data_collector_path=_data_collector_path, plan=plan)

What already works (no fix needed)

Scenario	Must-gathers	Why
Test 1 call FAILED, tests 2-6 xfail (@pytest.mark.incremental)	1	xfail doesn't trigger pytest_exception_interact
Test 1 call FAILED, tests 2-6 independent (no incremental)	Each gets its own	Correct — different test, different cluster state

What's broken

Scenario	Must-gathers	Should be
Class-scoped fixture fails → N tests get setup ERROR	N (e.g., 6)	1

Proposed Fix

Add deduplication in pytest_exception_interact for setup-phase errors only:

1. Track collected fixture errors per class using a session-level set (e.g., _must_gather_collected_fixtures) stored on the session object
2. For call.when == "setup" with class-based tests: build a dedup key from (node.cls, exception type, truncated exception message) — if already in the set, skip must-gather
3. For call.when == "call": always collect (no change — each test failure is potentially different, and @pytest.mark.incremental already handles dedup via xfail)

Implementation sketch

def pytest_exception_interact(node, call, report):
    if is_dry_run(node.session.config):
        return

    if not node.session.config.getoption("skip_data_collector"):
        # Deduplicate must-gather for shared fixture failures.
        # When a class-scoped fixture fails, ALL test methods in the class
        # get a setup ERROR — but must-gather only needs to run once.
        if call.when == "setup" and hasattr(node, "cls") and node.cls:
            collected = getattr(node.session, "_must_gather_collected_fixtures", set())
            dedup_key = (node.cls, str(type(call.excinfo.value)), str(call.excinfo.value)[:200])
            if dedup_key in collected:
                LOGGER.info(
                    f"Skipping duplicate must-gather for {node.name} "
                    "— same fixture error already collected for this class"
                )
                return
            collected.add(dedup_key)
            node.session._must_gather_collected_fixtures = collected

        _data_collector_path = Path(
            f"{node.session.config.getoption('data_collector_path')}/{sanitize_test_name_for_path(node.name)}"
        )
        plan = None
        if hasattr(node, "cls") and node.cls and hasattr(node.cls, "plan_resource"):
            plan_obj = node.cls.plan_resource
            if plan_obj:
                plan = {"name": plan_obj.name, "namespace": plan_obj.namespace}

        run_must_gather(data_collector_path=_data_collector_path, plan=plan)

Files to change

File	Change
conftest.py	Add setup-error dedup in pytest_exception_interact

Effort estimate

~30 minutes

Done

• Add setup-error dedup logic to pytest_exception_interact in conftest.py
• Verify: class fixture failure → 1 must-gather (not N)
• Verify: individual test call failures still collect must-gather independently
• Verify: @pytest.mark.incremental behavior unchanged (xfail skips still don't trigger must-gather)