add test case

Signed-off-by: aramissennyeydd <aramis.sennyey@doordash.com>

packages/backend-defaults/package.json

@@ -21,7 +21,6 @@
   "exports": {
     ".": "./src/index.ts",
     "./auditor": "./src/entrypoints/auditor/index.ts",
-    "./alpha": "./src/entrypoints/alpha.ts",
     "./auth": "./src/entrypoints/auth/index.ts",
     "./cache": "./src/entrypoints/cache/index.ts",
     "./database": "./src/entrypoints/database/index.ts",
@@ -50,9 +49,6 @@
       "auditor": [
         "src/entrypoints/auditor/index.ts"
       ],
-      "alpha": [
-        "src/entrypoints/alpha.ts"
-      ],
       "auth": [
         "src/entrypoints/auth/index.ts"
       ],
@@ -218,6 +214,7 @@
     "@types/yauzl": "^2.10.0",
     "aws-sdk-client-mock": "^4.0.0",
     "better-sqlite3": "^12.0.0",
+    "get-port": "^5.1.1",
     "http-errors": "^2.0.0",
     "msw": "^1.0.0",
     "node-mocks-http": "^1.0.0",

packages/backend-defaults/src/entrypoints/systemMetadata/SystemMetadataService.test.ts

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2025 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 { createSpecializedBackend } from '@backstage/backend-app-api';
+import { systemMetadataServiceFactory } from './systemMetadataServiceFactory';
+import { mockServices } from '@backstage/backend-test-utils';
+import getPort from 'get-port';
+import { createBackendPlugin } from '@backstage/backend-plugin-api';
+
+const baseFactories = [
+  mockServices.rootHealth.factory(),
+  mockServices.rootLogger.factory(),
+  mockServices.rootLifecycle.factory(),
+  mockServices.rootHttpRouter.factory(),
+  mockServices.lifecycle.factory(),
+  mockServices.logger.factory(),
+];
+
+describe('SystemMetadataService', () => {
+  it('should list plugins across instances', async () => {
+    const instance1HttpPort = await getPort();
+    const instance2HttpPort = await getPort();
+    const instance1 = createSpecializedBackend({
+      defaultServiceFactories: [
+        ...baseFactories,
+        systemMetadataServiceFactory,
+        mockServices.rootConfig.factory({
+          data: {
+            backend: {
+              listen: {
+                port: instance1HttpPort,
+              },
+            },
+            discovery: {
+              instances: [
+                {
+                  baseUrl: `http://localhost:${instance1HttpPort}`,
+                },
+                {
+                  baseUrl: `http://localhost:${instance2HttpPort}`,
+                },
+              ],
+            },
+          },
+        }),
+      ],
+    });
+
+    const instance2 = createSpecializedBackend({
+      defaultServiceFactories: [
+        ...baseFactories,
+        systemMetadataServiceFactory,
+        mockServices.rootConfig.factory({
+          data: {
+            backend: {
+              listen: {
+                port: instance2HttpPort,
+              },
+            },
+            discovery: {
+              instances: [
+                {
+                  baseUrl: `http://localhost:${instance1HttpPort}`,
+                },
+                {
+                  baseUrl: `http://localhost:${instance2HttpPort}`,
+                },
+              ],
+            },
+          },
+        }),
+      ],
+    });
+
+    instance1.add(
+      createBackendPlugin({
+        pluginId: 'test',
+        register(reg) {
+          reg.registerInit({
+            deps: {},
+            async init() {
+              // do nothing
+            },
+          });
+        },
+      }),
+    );
+
+    instance2.add(
+      createBackendPlugin({
+        pluginId: 'test-other',
+        register(reg) {
+          reg.registerInit({
+            deps: {},
+            async init() {
+              // do nothing
+            },
+          });
+        },
+      }),
+    );
+
+    await instance1.start();
+    await instance2.start();
+
+    const installedFeatures = await fetch(
+      `http://localhost:${instance1HttpPort}/.backstage/systemMetadata/v1/features/installed`,
+    );
+
+    expect(installedFeatures.status).toBe(200);
+
+    await expect(installedFeatures.json()).resolves.toMatchObject({
+      test: [
+        {
+          externalUrl: `http://localhost:${instance1HttpPort}`,
+          internalUrl: `http://localhost:${instance1HttpPort}`,
+        },
+      ],
+      'test-other': [
+        {
+          externalUrl: `http://localhost:${instance2HttpPort}`,
+          internalUrl: `http://localhost:${instance2HttpPort}`,
+        },
+      ],
+    });
+  });
+});

yarn.lock

@@ -2915,6 +2915,7 @@ __metadata:
     express-promise-router: "npm:^4.1.0"
     express-rate-limit: "npm:^7.5.0"
     fs-extra: "npm:^11.2.0"
+    get-port: "npm:^5.1.1"
     git-url-parse: "npm:^15.0.0"
     helmet: "npm:^6.0.0"
     http-errors: "npm:^2.0.0"