1 files changed, 79 insertions, 0 deletions
diff --git a/pkg/v1/cache/ro_test.go b/pkg/v1/cache/ro_test.go
new file mode 100644
index 0000000..4ec6b1c
--- /dev/null
+++ b/pkg/v1/cache/ro_test.go
@@ -0,0 +1,79 @@
+// Copyright 2021 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	"testing"
+
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/random"
+)
+
+func TestReadOnly(t *testing.T) {
+	m := &memcache{map[v1.Hash]v1.Layer{}}
+	ro := ReadOnly(m)
+
+	// Populate the cache.
+	img, err := random.Image(10, 1)
+	if err != nil {
+		t.Fatalf("random.Image: %v", err)
+	}
+	img = Image(img, m)
+	ls, err := img.Layers()
+	if err != nil {
+		t.Fatalf("Layers: %v", err)
+	}
+	if got, want := len(ls), 1; got != want {
+		t.Fatalf("Layers returned %d layers, want %d", got, want)
+	}
+	h, err := ls[0].Digest()
+	if err != nil {
+		t.Fatalf("layer.Digest: %v", err)
+	}
+	m.m[h] = ls[0]
+
+	// Layer can be read from original cache and RO cache.
+	if _, err := m.Get(h); err != nil {
+		t.Fatalf("m.Get: %v", err)
+	}
+	if _, err := ro.Get(h); err != nil {
+		t.Fatalf("ro.Get: %v", err)
+	}
+	ln := len(m.m)
+
+	// RO Put is a no-op.
+	if _, err := ro.Put(ls[0]); err != nil {
+		t.Fatalf("ro.Put: %v", err)
+	}
+	if got, want := len(m.m), ln; got != want {
+		t.Errorf("After Put, got %v entries, want %v", got, want)
+	}
+
+	// RO Delete is a no-op.
+	if err := ro.Delete(h); err != nil {
+		t.Fatalf("ro.Delete: %v", err)
+	}
+	if got, want := len(m.m), ln; got != want {
+		t.Errorf("After Delete, got %v entries, want %v", got, want)
+	}
+
+	// Deleting from the underlying RW cache updates RO view.
+	if err := m.Delete(h); err != nil {
+		t.Fatalf("m.Delete: %v", err)
+	}
+	if got, want := len(m.m), 0; got != want {
+		t.Errorf("After RW Delete, got %v entries, want %v", got, want)
+	}
+}