oci: loadArchive to import an index from a tar archive image bundle

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

__tests__/fixtures/hello.Dockerfile

@@ -14,7 +14,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM busybox
+FROM busybox AS build
 ARG NAME=foo
 ARG TARGETPLATFORM
-RUN echo "Hello $NAME from $TARGETPLATFORM"
+RUN echo "Hello $NAME from $TARGETPLATFORM" > foo
+
+FROM scratch
+COPY --from=build /foo /

__tests__/oci/oci.test.ts

@@ -0,0 +1,50 @@
+/**
+ * Copyright 2024 actions-toolkit 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.
+ */
+
+import {afterEach, beforeEach, describe, expect, jest, test} from '@jest/globals';
+import * as fs from 'fs';
+import path from 'path';
+import * as rimraf from 'rimraf';
+
+import {OCI} from '../../src/oci/oci';
+
+const fixturesDir = path.join(__dirname, '..', 'fixtures');
+
+// prettier-ignore
+const tmpDir = path.join(process.env.TEMP || '/tmp', 'docker-jest');
+
+beforeEach(() => {
+  jest.clearAllMocks();
+});
+
+afterEach(function () {
+  rimraf.sync(tmpDir);
+});
+
+describe('loadArchive', () => {
+  // prettier-ignore
+  test.each(fs.readdirSync(path.join(fixturesDir, 'oci-archive')).filter(file => {
+      return fs.statSync(path.join(path.join(fixturesDir, 'oci-archive'), file)).isFile();
+    }).map(filename => [filename]))('extracting %p', async (filename) => {
+    const res = await OCI.loadArchive({
+      file: path.join(fixturesDir, 'oci-archive', filename)
+    });
+    expect(res).toBeDefined();
+    expect(res?.root.index).toBeDefined();
+    expect(res?.root.layout).toBeDefined();
+    // console.log(JSON.stringify(res, null, 2));
+  });
+});