feat: support apiEndpoint override

package.json

@@ -46,7 +46,7 @@
     "predocs-test": "npm run docs"
   },
   "dependencies": {
-    "@google-cloud/common": "^1.0.0",
+    "@google-cloud/common": "^2.0.0",
     "@google-cloud/promisify": "^1.0.0",
     "arrify": "^2.0.0",
     "extend": "^3.0.1",
@@ -74,7 +74,7 @@
     "jsdoc": "^3.6.2",
     "jsdoc-baseline": "^0.1.0",
     "linkinator": "^1.1.2",
-    "mocha": "^6.0.0",
+    "mocha": "^6.1.4",
     "nyc": "^14.0.0",
     "power-assert": "^1.6.0",
     "prettier": "^1.13.5",

src/v2/index.ts

@@ -59,6 +59,11 @@ export interface TranslateConfig extends GoogleAuthOptions {
   key?: string;
   autoRetry?: boolean;
   maxRetries?: number;
+  /**
+   * The API endpoint of the service used to make requests.
+   * Defaults to `translation.googleapis.com`.
+   */
+  apiEndpoint?: string;
 }
 
 /**
@@ -120,14 +125,15 @@ export interface TranslateConfig extends GoogleAuthOptions {
 export class Translate extends Service {
   options: TranslateConfig;
   key?: string;
-  constructor(options?: TranslateConfig) {
-    let baseUrl = 'https://translation.googleapis.com/language/translate/v2';
-
+  constructor(options: TranslateConfig = {}) {
+    options.apiEndpoint = options.apiEndpoint || 'translation.googleapis.com';
+    let baseUrl = `https://${options.apiEndpoint}/language/translate/v2`;
     if (process.env.GOOGLE_CLOUD_TRANSLATE_ENDPOINT) {
       baseUrl = process.env.GOOGLE_CLOUD_TRANSLATE_ENDPOINT.replace(/\/+$/, '');
     }
 
     const config = {
+      apiEndpoint: options.apiEndpoint,
       baseUrl,
       scopes: ['https://www.googleapis.com/auth/cloud-platform'],
       packageJson: require('../../../package.json'),

test/index.ts

@@ -110,6 +110,16 @@ describe('Translate v2', () => {
       assert.strictEqual(calledWith.projectIdRequired, false);
     });
 
+    it('should allow apiEndpoint override', () => {
+      const apiEndpoint = 'fake.endpoint';
+      translate = new Translate({
+        projectId: 'test-project',
+        apiEndpoint,
+      });
+      const calledWith = translate.calledWith_[0];
+      assert.strictEqual(calledWith.apiEndpoint, apiEndpoint);
+    });
+
     describe('Using an API Key', () => {
       const KEY_OPTIONS = {
         key: 'api-key',