feat: export NowFunc config to help tests (#242)

* feat: export NewFunc config to help tests

Change-Id: I5be347f6de157380d963246f0c03d7c9ca9f4585

* feat: export NewFunc config to help tests

Change-Id: Ibce615c1ce7fd486b65a5b691a140e82efad12ca

Co-authored-by: guxi.reasno <guxi.reasno@bytedance.com>

cron/config.go

@@ -16,4 +16,6 @@ type Config struct {
 	GlobalOptions []JobOption
 	// EnableSeconds is whether to enable seconds in the cron expression.
 	EnableSeconds bool
+	// NowFunc Allows the user to mock the current time.
+	NowFunc func() time.Time
 }

cron/cron.go

@@ -23,6 +23,7 @@ type Cron struct {
 	location         *time.Location
 	nextID           int
 	quitWaiter       sync.WaitGroup
+	nowFunc          func() time.Time
 }
 
 // New returns a new Cron instance.
@@ -34,6 +35,7 @@ func New(config Config) *Cron {
 		globalMiddleware: config.GlobalOptions,
 		location:         config.Location,
 		nextID:           1,
+		nowFunc:          config.NowFunc,
 	}
 	if config.Parser == nil {
 		if config.EnableSeconds {
@@ -173,6 +175,9 @@ func (c *Cron) Run(ctx context.Context) error {
 }
 
 func (c *Cron) now() time.Time {
+	if c.nowFunc != nil {
+		return c.nowFunc()
+	}
 	return time.Now().In(c.location)
 }
 

cron/cron_test.go

@@ -92,3 +92,26 @@ func TestCron_remove_job(t *testing.T) {
 	case <-time.After(2 * time.Millisecond):
 	}
 }
+
+func TestCron_nowFunc(t *testing.T) {
+	t.Parallel()
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Millisecond)
+	defer cancel()
+
+	fakeNow, _ := time.Parse("2006-01-02 15:04:05", "2019-01-01 00:00:00")
+	c := New(Config{NowFunc: func() time.Time {
+		return fakeNow.Add(-time.Microsecond)
+	}})
+	go c.Run(ctx)
+
+	ch := make(chan struct{})
+	c.Add("0 0 * * *", func(ctx context.Context) error {
+		ch <- struct{}{}
+		return nil
+	})
+	select {
+	case <-ch:
+	case <-time.After(2 * time.Millisecond):
+		t.Fatal("timeout")
+	}
+}