bots: Add test file for 'giphy' bot.

This bot replies with different gif for the same query
that is provided. Mocked a definite response from requests.get
function.

bots/giphy/test_giphy.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python
+
+from __future__ import absolute_import
+from __future__ import print_function
+
+import os
+import sys
+import json
+
+our_dir = os.path.dirname(os.path.abspath(__file__))
+sys.path.insert(0, os.path.normpath(os.path.join(our_dir)))
+# For dev setups, we can find the API in the repo itself.
+if os.path.exists(os.path.join(our_dir, '..')):
+    sys.path.insert(0, '..')
+from bots_test_lib import BotTestCase
+from bots.giphy import giphy
+
+def get_http_response_json(gif_url):
+    response_json = {
+        'meta': {
+            'status': 200
+        },
+        'data': {
+            'images': {
+                'original': {
+                    'url': gif_url
+                }
+            }
+        }
+    }
+    return response_json
+
+def get_bot_response(gif_url):
+    return ('[Click to enlarge](%s)'
+            '[](/static/images/interactive-bot/giphy/powered-by-giphy.png)'
+            % (gif_url))
+
+def get_http_request(keyword):
+    return {
+        'api_url': giphy.GIPHY_TRANSLATE_API,
+        'params': {
+            's': keyword,
+            'api_key': giphy.get_giphy_api_key_from_config()
+        }
+    }
+
+class TestGiphyBot(BotTestCase):
+    bot_name = "giphy"
+
+    def test_bot(self):
+        # This message calls `send_reply` function of BotHandlerApi
+        keyword = "Hello"
+        gif_url = "https://media4.giphy.com/media/3o6ZtpxSZbQRRnwCKQ/giphy.gif"
+        expectations = {
+            keyword: get_bot_response(gif_url)
+        }
+        self.check_expected_responses(
+            expectations=expectations,
+            http_request=get_http_request(keyword),
+            http_response=get_http_response_json(gif_url)
+        )