Add usage calculation test

Signed-off-by: Derek McGowan <derek@mcg.dev>

images/usage/calculator_test.go

@@ -0,0 +1,100 @@
+/*
+   Copyright The containerd Authors.
+
+   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 usage
+
+import (
+	"context"
+	"testing"
+
+	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/images/imagetest"
+	"github.com/containerd/containerd/platforms"
+	"github.com/containerd/log/logtest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+func TestUsageCalculation(t *testing.T) {
+	for _, tc := range []struct {
+		name     string
+		target   imagetest.ContentCreator
+		expected imagetest.ContentSizeCalculator
+		opts     []Opt
+	}{
+		{
+			name:     "simple",
+			target:   imagetest.SimpleManifest(50),
+			expected: imagetest.SizeOfManifest,
+			opts:     []Opt{WithManifestUsage()},
+		},
+		{
+			name:     "simpleIndex",
+			target:   imagetest.SimpleIndex(5, 50),
+			expected: imagetest.SizeOfContent,
+		},
+		{
+			name:     "stripLayersManifestOnly",
+			target:   imagetest.StripLayers(imagetest.SimpleIndex(3, 51)),
+			expected: imagetest.SizeOfManifest,
+			opts:     []Opt{WithManifestUsage()},
+		},
+		{
+			name:     "stripLayers",
+			target:   imagetest.StripLayers(imagetest.SimpleIndex(4, 60)),
+			expected: imagetest.SizeOfContent,
+		},
+		{
+			name: "manifestlimit",
+			target: func(tc imagetest.ContentStore) imagetest.Content {
+				return tc.Index(
+					imagetest.AddPlatform(imagetest.SimpleManifest(5)(tc), ocispec.Platform{Architecture: "amd64", OS: "linux"}),
+					imagetest.AddPlatform(imagetest.SimpleManifest(10)(tc), ocispec.Platform{Architecture: "arm64", OS: "linux"}),
+				)
+			},
+			expected: func(t imagetest.Content) int64 { return imagetest.SizeOfManifest(imagetest.LimitChildren(t, 1)) },
+			opts: []Opt{
+				WithManifestLimit(platforms.Only(ocispec.Platform{Architecture: "amd64", OS: "linux"}), 1),
+				WithManifestUsage(),
+			},
+		},
+		// TODO: Add test with snapshot
+	} {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			ctx := logtest.WithT(context.Background(), t)
+
+			cs := imagetest.NewContentStore(ctx, t)
+			content := tc.target(cs)
+			img := images.Image{
+				Name:   tc.name,
+				Target: content.Descriptor,
+				Labels: content.Labels,
+			}
+
+			usage, err := CalculateImageUsage(ctx, img, cs, tc.opts...)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			expected := tc.expected(content)
+
+			if expected != usage {
+				t.Fatalf("unexpected usage: %d, expected %d", usage, expected)
+			}
+		})
+	}
+
+}