Create image reference cache.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/image_status_test.go

@@ -31,11 +31,13 @@ import (
 func TestImageStatus(t *testing.T) {
 	testID := "sha256:d848ce12891bf78792cda4a23c58984033b0c397a55e93a1556202222ecc5ed4"
 	image := imagestore.Image{
-		ID:          testID,
-		ChainID:     "test-chain-id",
-		RepoTags:    []string{"a", "b"},
-		RepoDigests: []string{"c", "d"},
-		Size:        1234,
+		ID:      testID,
+		ChainID: "test-chain-id",
+		References: []string{
+			"gcr.io/library/busybox:latest",
+			"gcr.io/library/busybox@sha256:e6693c20186f837fc393390135d8a598a96a833917917789d63766cab6c59582",
+		},
+		Size: 1234,
 		ImageSpec: imagespec.Image{
 			Config: imagespec.ImageConfig{
 				User: "user:group",
@@ -44,8 +46,8 @@ func TestImageStatus(t *testing.T) {
 	}
 	expected := &runtime.Image{
 		Id:          testID,
-		RepoTags:    []string{"a", "b"},
-		RepoDigests: []string{"c", "d"},
+		RepoTags:    []string{"gcr.io/library/busybox:latest"},
+		RepoDigests: []string{"gcr.io/library/busybox@sha256:e6693c20186f837fc393390135d8a598a96a833917917789d63766cab6c59582"},
 		Size_:       uint64(1234),
 		Username:    "user",
 	}
@@ -59,7 +61,8 @@ func TestImageStatus(t *testing.T) {
 	require.NotNil(t, resp)
 	assert.Nil(t, resp.GetImage())
 
-	c.imageStore.Add(image)
+	c.imageStore, err = imagestore.NewFakeStore([]imagestore.Image{image})
+	assert.NoError(t, err)
 
 	t.Logf("should return correct image status for exist image")
 	resp, err = c.ImageStatus(context.Background(), &runtime.ImageStatusRequest{