add test for initializePerforamnce

Author: Feiyang1

packages-exp/performance-exp/src/index.test.ts

@@ -0,0 +1,50 @@
+/**
+ * @license
+ * Copyright 2020 Google LLC
+ *
+ * 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 { expect } from 'chai';
+import { stub } from 'sinon';
+import { initializePerformance } from './index';
+import { ERROR_FACTORY, ErrorCode } from './utils/errors';
+import * as firebase from '@firebase/app-exp';
+import { Provider } from '@firebase/component';
+import '../test/setup';
+
+const fakeFirebaseConfig = {
+  apiKey: 'api-key',
+  authDomain: 'project-id.firebaseapp.com',
+  databaseURL: 'https://project-id.firebaseio.com',
+  projectId: 'project-id',
+  storageBucket: 'project-id.appspot.com',
+  messagingSenderId: 'sender-id',
+  appId: '1:111:web:a1234'
+};
+
+const fakeFirebaseApp = ({
+  options: fakeFirebaseConfig
+} as unknown) as firebase.FirebaseApp;
+
+describe('Firebase Performance > initializePerformance()', () => {
+  it('throws if a perf instance has already been created', () => {
+    stub(firebase, '_getProvider').returns(({
+      isInitialized: () => true
+    } as unknown) as Provider<'performance-exp'>);
+    const expectedError = ERROR_FACTORY.create(ErrorCode.ALREADY_INITIALIZED);
+    expect(() => initializePerformance(fakeFirebaseApp)).to.throw(
+      expectedError.message
+    );
+  });
+});

packages-exp/performance-exp/src/utils/string_merger.test.ts

@@ -19,13 +19,11 @@ import { expect } from 'chai';
 
 import { mergeStrings } from './string_merger';
 import { FirebaseError } from '@firebase/util';
-// import { ERROR_FACTORY, ErrorCode } from './errors';
 import '../../test/setup';
 
 describe('Firebase Performance > string_merger', () => {
   describe('#mergeStrings', () => {
     it('Throws exception when string length has | diff | > 1', () => {
-      // const expectedError = ERROR_FACTORY.create(ErrorCode.INVALID_STRING_MERGER_PARAMETER);
       expect(() => mergeStrings('', '123')).to.throw(
         FirebaseError,
         'performance/invalid String merger input'