fake util.clock tick

pkg/util/clock_test.go

@@ -104,3 +104,81 @@ func TestFakeAfter(t *testing.T) {
 		t.Errorf("unexpected non-channel read")
 	}
 }
+
+func TestFakeTick(t *testing.T) {
+	tc := NewFakeClock(time.Now())
+	if tc.HasWaiters() {
+		t.Errorf("unexpected waiter?")
+	}
+	oneSec := tc.Tick(time.Second)
+	if !tc.HasWaiters() {
+		t.Errorf("unexpected lack of waiter?")
+	}
+
+	oneOhOneSec := tc.Tick(time.Second + time.Millisecond)
+	twoSec := tc.Tick(2 * time.Second)
+	select {
+	case <-oneSec:
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+	}
+
+	tc.Step(999 * time.Millisecond) // t=.999
+	select {
+	case <-oneSec:
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+	}
+
+	tc.Step(time.Millisecond) // t=1.000
+	select {
+	case <-oneSec:
+		// Expected!
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+		t.Errorf("unexpected non-channel read")
+	}
+	tc.Step(time.Millisecond) // t=1.001
+	select {
+	case <-oneSec:
+		// should not double-trigger!
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		// Expected!
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+		t.Errorf("unexpected non-channel read")
+	}
+
+	tc.Step(time.Second) // t=2.001
+	tc.Step(time.Second) // t=3.001
+	tc.Step(time.Second) // t=4.001
+	tc.Step(time.Second) // t=5.001
+
+	// The one second ticker should not accumulate ticks
+	accumulatedTicks := 0
+	drained := false
+	for !drained {
+		select {
+		case <-oneSec:
+			accumulatedTicks++
+		default:
+			drained = true
+		}
+	}
+	if accumulatedTicks != 1 {
+		t.Errorf("unexpected number of accumulated ticks: %d", accumulatedTicks)
+	}
+}