core-plugin-api: Add tests and changesets

Co-authored-by: blam <ben@blam.sh>
Co-authored-by: Patrik Oldsberg <poldsberg@gmail.com>
Signed-off-by: Johan Haals <johan.haals@gmail.com>

.changeset/slow-olives-confess.md

@@ -0,0 +1,7 @@
+---
+'@backstage/core-plugin-api': patch
+---
+
+Deprecated `register` option of `createPlugin` and the `outputs` methods of the plugin instance.
+
+Introduces the `featureFlags` property to define your feature flags instead.

.changeset/young-hats-shop.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-cost-insights': patch
+---
+
+Supply featureFlags using featureFlag config option.

packages/core-app-api/src/app/AppManager.test.tsx

@@ -349,6 +349,78 @@ describe('Integration Test', () => {
     });
   });
 
+  it('getFeatureFlags should return feature flags', async () => {
+    const storageFlags = new LocalStorageFeatureFlags();
+    jest.spyOn(storageFlags, 'registerFlag');
+
+    const apis = [
+      noOpAnalyticsApi,
+      createApiFactory({
+        api: featureFlagsApiRef,
+        deps: { configApi: configApiRef },
+        factory() {
+          return storageFlags;
+        },
+      }),
+    ];
+
+    const app = new AppManager({
+      apis,
+      defaultApis: [],
+      themes: [
+        {
+          id: 'light',
+          title: 'Light Theme',
+          variant: 'light',
+          Provider: ({ children }) => <>{children}</>,
+        },
+      ],
+      icons,
+      plugins: [
+        createPlugin({
+          id: 'test',
+          featureFlags: [
+            {
+              name: 'foo',
+            },
+          ],
+          register: p => p.featureFlags.register('name'),
+        }),
+      ],
+      components,
+      configLoader: async () => [],
+      bindRoutes: ({ bind }) => {
+        bind(plugin1.externalRoutes, {
+          extRouteRef1: plugin1RouteRef,
+          extRouteRef2: plugin2RouteRef,
+        });
+      },
+    });
+
+    const Provider = app.getProvider();
+    const Router = app.getRouter();
+
+    await renderWithEffects(
+      <Provider>
+        <Router>
+          <Routes>
+            <Route path="/" element={<ExposedComponent />} />
+            <Route path="/foo" element={<HiddenComponent />} />
+          </Routes>
+        </Router>
+      </Provider>,
+    );
+
+    expect(storageFlags.registerFlag).toHaveBeenCalledWith({
+      name: 'name',
+      pluginId: 'test',
+    });
+    expect(storageFlags.registerFlag).toHaveBeenCalledWith({
+      name: 'foo',
+      pluginId: 'test',
+    });
+  });
+
   it('should track route changes via analytics api', async () => {
     const mockAnalyticsApi = new MockAnalyticsApi();
     const apis = [createApiFactory(analyticsApiRef, mockAnalyticsApi)];

packages/core-plugin-api/src/plugin/Plugin.test.tsx

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2021 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 { createPlugin } from './Plugin';
+
+describe('Plugin Feature Flag', () => {
+  it('should be able to register and receive feature flags', () => {
+    expect(
+      createPlugin({
+        id: 'test',
+        featureFlags: [{ name: 'test' }],
+      }).getFeatureFlags(),
+    ).toEqual([{ name: 'test' }]);
+
+    expect(
+      createPlugin({
+        id: 'test',
+        register({ featureFlags }) {
+          featureFlags.register('blob');
+        },
+      }).getFeatureFlags(),
+    ).toEqual([{ name: 'blob' }]);
+
+    expect(
+      createPlugin({
+        id: 'test',
+        register({ featureFlags }) {
+          featureFlags.register('blob');
+        },
+        featureFlags: [{ name: 'test' }],
+      }).getFeatureFlags(),
+    ).toEqual([{ name: 'test' }, { name: 'blob' }]);
+
+    expect(
+      createPlugin({
+        id: 'test',
+      }).getFeatureFlags(),
+    ).toEqual([]);
+
+    /* deprecated tests */
+
+    expect(
+      createPlugin({
+        id: 'test',
+        featureFlags: [{ name: 'test' }],
+      }).output(),
+    ).toEqual([{ name: 'test', type: 'feature-flag' }]);
+
+    expect(
+      createPlugin({
+        id: 'test',
+        register({ featureFlags }) {
+          featureFlags.register('blob');
+        },
+      }).output(),
+    ).toEqual([{ name: 'blob', type: 'feature-flag' }]);
+    expect(
+      createPlugin({
+        id: 'test',
+        register({ featureFlags }) {
+          featureFlags.register('blob');
+        },
+        featureFlags: [{ name: 'test' }],
+      }).output(),
+    ).toEqual([
+      { name: 'test', type: 'feature-flag' },
+      { name: 'blob', type: 'feature-flag' },
+    ]);
+
+    expect(
+      createPlugin({
+        id: 'test',
+      }).output(),
+    ).toEqual([]);
+  });
+});