Method TestContextCanceled

test/context_canceled_test.go:37–116

(t *testing.T)

)

func (s) TestContextCanceled(t *testing.T) {
	ss := &stubserver.StubServer{
		FullDuplexCallF: func(stream testgrpc.TestService_FullDuplexCallServer) error {
			stream.SetTrailer(metadata.New(map[string]string{"a": "b"}))
			return status.Error(codes.PermissionDenied, "perm denied")
		},
	}
	if err := ss.Start(nil); err != nil {
		t.Fatalf("Error starting endpoint server: %v", err)
	}
	defer ss.Stop()

	// Runs 10 rounds of tests with the given delay and returns counts of status codes.
	// Fails in case of trailer/status code inconsistency.
	const cntRetry uint = 10
	runTest := func(delay time.Duration) (cntCanceled, cntPermDenied uint) {
		for i := uint(0); i < cntRetry; i++ {
			ctx, cancel := context.WithTimeout(context.Background(), delay)
			defer cancel()

			str, err := ss.Client.FullDuplexCall(ctx)
			if err != nil {
				continue
			}

			_, err = str.Recv()
			if err == nil {
				t.Fatalf("non-nil error expected from Recv()")
			}

			_, trlOk := str.Trailer()["a"]
			switch status.Code(err) {
			case codes.PermissionDenied:
				if !trlOk {
					t.Fatalf(`status err: %v; wanted key "a" in trailer but didn't get it`, err)
				}
				cntPermDenied++
			case codes.DeadlineExceeded:
				if trlOk {
					t.Fatalf(`status err: %v; didn't want key "a" in trailer but got it`, err)
				}
				cntCanceled++
			default:
				t.Fatalf(`unexpected status err: %v`, err)
			}
		}
		return cntCanceled, cntPermDenied
	}

	// Tries to find the delay that causes canceled/perm denied race.
	canceledOk, permDeniedOk := false, false
	for lower, upper := time.Duration(0), 2*time.Millisecond; lower <= upper; {
		delay := lower + (upper-lower)/2
		cntCanceled, cntPermDenied := runTest(delay)
		if cntPermDenied > 0 && cntCanceled > 0 {
			// Delay that causes the race is found.
			return
		}