google_translate bot: Add test for invalid api key.

zulip_bots/zulip_bots/bots/google_translate/fixtures/test_invalid_api_key.json

@@ -0,0 +1,28 @@
+{
+  "request": {
+    "method": "GET",
+    "api_url": "https://translation.googleapis.com/language/translate/v2/languages",
+    "params": {
+      "key": "abcdefg",
+      "target": "en"
+    }
+  },
+  "response": {
+    "error":{  
+      "status": "INVALID_ARGUMENT",
+      "message": "API key not valid. Please pass a valid API key.",
+      "code": 400,
+      "errors": [  
+        {  
+          "domain":"global",
+          "message":"API key not valid. Please pass a valid API key.",
+          "reason":"badRequest"
+        }
+      ]
+    }
+  },
+  "response-headers": {
+    "status": 400,
+    "content-type": "application/json; charset=utf-8"
+  }
+}

zulip_bots/zulip_bots/bots/google_translate/test_google_translate.py

@@ -66,6 +66,10 @@ class TestGoogleTranslateBot(BotTestCase):
                    side_effect=Exception):
             self._test('"hello" de', 'Error. .', 'test_languages')
 
+    def test_invalid_api_key(self):
+        with self.assertRaises(StubBotHandler.BotQuitException):
+            self._test(None, None, 'test_invalid_api_key')
+
     def test_api_access_not_configured(self):
         with self.assertRaises(StubBotHandler.BotQuitException):
             self._test(None, None, 'test_api_access_not_configured')