Function TestFutureConcurrent

ch04/future_test.go:86–114

TestFutureConcurrent tests that the Future is thread-safe.

(t *testing.T)

// TestFutureConcurrent tests that the Future is thread-safe.
func TestFutureConcurrent(t *testing.T) {
	start := time.Now()

	ctx := context.Background()
	future := SlowFunction(ctx)

	var wg sync.WaitGroup

	for i := 0; i < 1000; i++ {
		wg.Add(1)

		go func() {
			defer wg.Done()
			res, err := future.Result()
			if err != nil {
				t.Error(err)
				return
			}

			if !strings.HasPrefix(res, "I slept for") {
				t.Error("unexpected output:", res)
			}

			elapsedCheck(t, start, 2)
		}()
	}

	wg.Wait()
}

// TestFutureTimeout makes sure that the future will time out with an error
// if its context is canceled with a timeout