Summary

The entire node/app/component test package never runs: TestMain calls os.Exit(0) without m.Run().

// node/app/component/component_test.go
func TestMain(m *testing.M) {
	_ = m
	os.Exit(0)
}

Introduced in ee703e2 (a [wip] ci: commit). As a result go test ./node/app/component/ reports ok while running zero tests — including the gomock lifecycle tests, event_flow_test.go, the fuzz tests, and all of hierarchy_test.go.

Why it can't simply be re-enabled yet

Switching to os.Exit(m.Run()) and running under -race / repeated counts exposes:

1. Data race on eventBus.prevQueueSize — ✅ fixed in node/app/event: fix data race on eventBus.prevQueueSize #21551.
2. TestEvents is flaky — c.EventBus("t") returns a shared/global bus whose subscriptions are not torn down between tests, so bus.Post("test") returns 3/5/7… instead of 2 as leaked handlers from earlier tests accumulate (component_test.go:652).
3. Goroutine leak → deadlock — under -race -count=20 the suite times out with ~464 leaked goroutines: ~397 component actor goroutines (component.go:320/:465) blocked on chan receive (never shut down), plus workerpool/event workers blocked on chan send. The execpool saturates and the run hangs.

Items 2 and 3 share a root cause: a test-isolation / lifecycle-teardown gap — components and their event subscriptions/goroutines are not cleaned up between tests (and/or a shared root bus persists global state across tests).

Suggested direction

• Give each test isolated component-domain/bus state, and/or ensure domain Close() stops all actor goroutines and clears subscriptions, with t.Cleanup in the tests.
• Once the suite is race-clean and leak-free under repeated -race runs, replace os.Exit(0) with os.Exit(m.Run()).

Context

Found while reviewing #21455 (unskip disabled tests). That PR leaves the three gomock lifecycle tests skipped and does not touch TestMain; this issue tracks turning the package back on properly.

cc @AskAlexSharov (introduced the os.Exit(0) in ee703e2)