Function TestDrainErrGroupReturnsError

utils/drain_test.go:15–28

TestDrainErrGroupReturnsError verifies the normal path: when the group's goroutines finish before the timeout, DrainErrGroup returns g.Wait()'s error verbatim (and does not wait out the timeout).

(t *testing.T)

// goroutines finish before the timeout, DrainErrGroup returns g.Wait()'s error
// verbatim (and does not wait out the timeout).
func TestDrainErrGroupReturnsError(t *testing.T) {
	var g errgroup.Group
	want := errors.New("boom")
	g.Go(func() error { return want })

	start := time.Now()
	got := DrainErrGroup(zap.NewNop(), "test", &g, time.Second)
	if !errors.Is(got, want) {
		t.Fatalf("DrainErrGroup err = %v, want %v", got, want)
	}
	if elapsed := time.Since(start); elapsed > 500*time.Millisecond {
		t.Fatalf("DrainErrGroup blocked for %s on a fast group; should return immediately", elapsed)
	}
}

// TestDrainErrGroupTimesOutOnHang is the regression guard for the shutdown
// deadlock: a goroutine that ignores cancellation (here, blocks forever) must