backend-test-utils: initial directory mock implementation

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/backend-test-utils/package.json

@@ -50,6 +50,7 @@
     "@backstage/types": "workspace:^",
     "better-sqlite3": "^8.0.0",
     "express": "^4.17.1",
+    "fs-extra": "^10.0.1",
     "knex": "^2.0.0",
     "msw": "^1.0.0",
     "mysql2": "^2.2.5",

packages/backend-test-utils/src/files/DirectoryMocker.ts

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2023 The Backstage 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 { resolveSafeChildPath } from '@backstage/backend-common';
+import fs from 'fs-extra';
+import { tmpdir as getTmpDir } from 'os';
+import { join as joinPath } from 'path';
+
+type FileNode = string | Buffer;
+
+type DirectoryNode = {
+  [name in string]: MockDirectoryNode;
+};
+
+type MockDirectoryNode = DirectoryNode | FileNode;
+
+export class DirectoryMocker {
+  static create() {
+    const root = fs.mkdtempSync(
+      joinPath(getTmpDir(), 'backstage-tmp-test-dir-'),
+    );
+
+    const mocker = new DirectoryMocker(root);
+
+    process.on('beforeExit', mocker.#cleanupSync);
+
+    afterAll(async () => {
+      await mocker.cleanup();
+    });
+
+    return mocker;
+  }
+
+  readonly #root: string;
+
+  private constructor(root: string) {
+    this.#root = root;
+  }
+
+  get dir() {
+    return this.#root;
+  }
+
+  async setContent(root: MockDirectoryNode) {
+    await this.cleanup();
+
+    async function createFiles(node: MockDirectoryNode, path: string) {
+      if (typeof node === 'string' || node instanceof Buffer) {
+        await fs.writeFile(path, node, 'utf8');
+        return;
+      }
+
+      await fs.ensureDir(path);
+
+      for (const [name, child] of Object.entries(node)) {
+        await createFiles(child, resolveSafeChildPath(path, name));
+      }
+    }
+
+    await createFiles(root, this.#root);
+  }
+
+  async cleanup() {
+    await fs.rm(this.#root, { recursive: true, force: true });
+  }
+
+  #cleanupSync() {
+    fs.rmSync(this.#root, { recursive: true, force: true });
+  }
+}

packages/backend-test-utils/src/files/index.ts

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2023 The Backstage 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.
+ */
+
+export { DirectoryMocker } from './DirectoryMocker';

packages/backend-test-utils/src/index.ts

@@ -22,5 +22,6 @@
 
 export * from './database';
 export * from './msw';
+export * from './files';
 export * from './next';
 export * from './util';

yarn.lock

@@ -3649,6 +3649,7 @@ __metadata:
     "@types/supertest": ^2.0.8
     better-sqlite3: ^8.0.0
     express: ^4.17.1
+    fs-extra: ^10.0.1
     knex: ^2.0.0
     msw: ^1.0.0
     mysql2: ^2.2.5