Add cache unit test

Test base functionality of the cache statter

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

registry/storage/cache/cache_test.go

@@ -0,0 +1,131 @@
+package cache
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/docker/distribution"
+	digest "github.com/opencontainers/go-digest"
+)
+
+func TestCacheSet(t *testing.T) {
+	cache := newTestStatter()
+	backend := newTestStatter()
+	st := NewCachedBlobStatter(cache, backend)
+	ctx := context.Background()
+
+	dgst := digest.Digest("dontvalidate")
+	_, err := st.Stat(ctx, dgst)
+	if err != distribution.ErrBlobUnknown {
+		t.Fatalf("Unexpected error %v, expected %v", err, distribution.ErrBlobUnknown)
+	}
+
+	desc := distribution.Descriptor{
+		Digest: dgst,
+	}
+	if err := backend.SetDescriptor(ctx, dgst, desc); err != nil {
+		t.Fatal(err)
+	}
+
+	actual, err := st.Stat(ctx, dgst)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if actual.Digest != desc.Digest {
+		t.Fatalf("Unexpected descriptor %v, expected %v", actual, desc)
+	}
+
+	if len(cache.sets) != 1 || len(cache.sets[dgst]) == 0 {
+		t.Fatalf("Expected cache set")
+	}
+	if cache.sets[dgst][0].Digest != desc.Digest {
+		t.Fatalf("Unexpected descriptor %v, expected %v", cache.sets[dgst][0], desc)
+	}
+
+	desc2 := distribution.Descriptor{
+		Digest: digest.Digest("dontvalidate 2"),
+	}
+	cache.sets[dgst] = append(cache.sets[dgst], desc2)
+
+	actual, err = st.Stat(ctx, dgst)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if actual.Digest != desc2.Digest {
+		t.Fatalf("Unexpected descriptor %v, expected %v", actual, desc)
+	}
+}
+
+func TestCacheError(t *testing.T) {
+	cache := newErrTestStatter(errors.New("cache error"))
+	backend := newTestStatter()
+	st := NewCachedBlobStatter(cache, backend)
+	ctx := context.Background()
+
+	dgst := digest.Digest("dontvalidate")
+	_, err := st.Stat(ctx, dgst)
+	if err != distribution.ErrBlobUnknown {
+		t.Fatalf("Unexpected error %v, expected %v", err, distribution.ErrBlobUnknown)
+	}
+
+	desc := distribution.Descriptor{
+		Digest: dgst,
+	}
+	if err := backend.SetDescriptor(ctx, dgst, desc); err != nil {
+		t.Fatal(err)
+	}
+
+	actual, err := st.Stat(ctx, dgst)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if actual.Digest != desc.Digest {
+		t.Fatalf("Unexpected descriptor %v, expected %v", actual, desc)
+	}
+
+	if len(cache.sets) > 0 {
+		t.Fatalf("Set should not be called after stat error")
+	}
+}
+
+func newTestStatter() *testStatter {
+	return &testStatter{
+		stats: []digest.Digest{},
+		sets:  map[digest.Digest][]distribution.Descriptor{},
+	}
+}
+
+func newErrTestStatter(err error) *testStatter {
+	return &testStatter{
+		sets: map[digest.Digest][]distribution.Descriptor{},
+		err:  err,
+	}
+}
+
+type testStatter struct {
+	stats []digest.Digest
+	sets  map[digest.Digest][]distribution.Descriptor
+	err   error
+}
+
+func (s *testStatter) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
+	if s.err != nil {
+		return distribution.Descriptor{}, s.err
+	}
+
+	if set := s.sets[dgst]; len(set) > 0 {
+		return set[len(set)-1], nil
+	}
+
+	return distribution.Descriptor{}, distribution.ErrBlobUnknown
+}
+
+func (s *testStatter) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
+	s.sets[dgst] = append(s.sets[dgst], desc)
+	return s.err
+}
+
+func (s *testStatter) Clear(ctx context.Context, dgst digest.Digest) error {
+	return s.err
+}