Add tests for ImageToCache/Daemon that they prevent multiple downloads.

pkg/minikube/download/download_test.go

@@ -130,3 +130,61 @@ func TestPreloadDownloadPreventsMultipleDownload(t *testing.T) {
 		t.Errorf("Wrong number of downloads occurred. Actual: %v, Expected: 1", tlog.downloads)
 	}
 }
+
+func TestImageToCache(t *testing.T) {
+	EnableMock(true)
+	defer EnableMock(false)
+	tlog := &mockLogger{downloads: 0, t: t}
+
+	klog.SetLogger(tlog)
+	defer klog.SetLogger(nil)
+
+	checkImageExistsInCache = func(img string) bool { return tlog.downloads > 0 }
+
+	var group sync.WaitGroup
+	group.Add(2)
+	dlCall := func() {
+		if err := ImageToCache("testimg"); err != nil {
+			t.Errorf("Failed to download preload: %+v", err)
+		}
+		group.Done()
+	}
+
+	go dlCall()
+	go dlCall()
+
+	group.Wait()
+
+	if tlog.downloads != 1 {
+		t.Errorf("Wrong number of downloads occurred. Actual: %v, Expected: 1", tlog.downloads)
+	}
+}
+
+func TestImageToDaemon(t *testing.T) {
+	EnableMock(true)
+	defer EnableMock(false)
+	tlog := &mockLogger{downloads: 0, t: t}
+
+	klog.SetLogger(tlog)
+	defer klog.SetLogger(nil)
+
+	checkImageExistsInCache = func(img string) bool { return tlog.downloads > 0 }
+
+	var group sync.WaitGroup
+	group.Add(2)
+	dlCall := func() {
+		if err := ImageToCache("testimg"); err != nil {
+			t.Errorf("Failed to download preload: %+v", err)
+		}
+		group.Done()
+	}
+
+	go dlCall()
+	go dlCall()
+
+	group.Wait()
+
+	if tlog.downloads != 1 {
+		t.Errorf("Wrong number of downloads occurred. Actual: %v, Expected: 1", tlog.downloads)
+	}
+}

pkg/minikube/download/image.go

@@ -60,6 +60,8 @@ func ImageExistsInCache(img string) bool {
 	return false
 }
 
+var checkImageExistsInCache = ImageExistsInCache
+
 // ImageExistsInDaemon if img exist in local docker daemon
 func ImageExistsInDaemon(img string) bool {
 	// Check if image exists locally
@@ -75,9 +77,11 @@ func ImageExistsInDaemon(img string) bool {
 	return false
 }
 
+var checkImageExistsInDaemon = ImageExistsInDaemon
+
 // ImageToCache writes img to the local cache directory
 func ImageToCache(img string) error {
-	if ImageExistsInCache(img) {
+	if checkImageExistsInCache(img) {
 		klog.Infof("%s exists in cache, skipping pull", img)
 		return nil
 	}
@@ -154,7 +158,7 @@ func ImageToCache(img string) error {
 
 // ImageToDaemon writes img to the local docker daemon
 func ImageToDaemon(img string) error {
-	if ImageExistsInDaemon(img) {
+	if checkImageExistsInDaemon(img) {
 		klog.Infof("%s exists in daemon, skipping pull", img)
 		return nil
 	}