diff --git a/requirements.txt b/requirements.txt
index 7d0095a72..a0aa31ce4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,3 +10,4 @@ pytest
 -e git+https://github.com/zulip/zulint@14e3974001bf8442a6a3486125865660f1f2eb68#egg=zulint==1.0.0
 mypy==0.812
 gitlint>=0.13.0
+responses
diff --git a/zulip/tests/test_api.py b/zulip/tests/test_api.py
new file mode 100644
index 000000000..c93824884
--- /dev/null
+++ b/zulip/tests/test_api.py
@@ -0,0 +1,95 @@
+import json
+import unittest
+import responses
+import zulip
+import urllib
+
+from typing import Any, Tuple, Dict
+from unittest import TestCase
+
+class TerminationException(Exception):
+    pass
+
+class TestAPI(TestCase):
+
+    @responses.activate
+    def test_add_reaction(self) -> None:
+        def request_callback(request: Any) -> Tuple[int, Dict[str, str], str]:
+            params = {}
+            for param in request.body.split("&"):
+                key, value = param.split("=")
+                params[key] = urllib.parse.unquote(value)
+            assert "emoji_name" in params or "emoji_code" in params
+            return (200, {}, json.dumps({'result': 'success', 'msg': ''}))
+
+        responses.add_callback(
+            method=responses.POST,
+            url="https://test.zulipapi.com/api/v1/messages/10/reactions",
+            callback=request_callback
+        )
+
+        client = zulip.Client(config_file="zulip/tests/test_zuliprc")
+        # request with emoji name
+        request = {
+            "message_id": 10,
+            "emoji_name": "octopus",
+        }
+        result = client.add_reaction(request)
+        self.assertEqual(result, {'result': 'success', 'msg': ''})
+        # request with emoji code
+        request = {
+            "message_id": 10,
+            "emoji_code": "1f419",
+        }
+        result = client.add_reaction(request)
+        self.assertEqual(result, {'result': 'success', 'msg': ''})
+
+    @responses.activate
+    def test_call_on_each_event(self) -> None:
+
+        responses.add(
+            responses.POST,
+            url="https://test.zulipapi.com/api/v1/register",
+            json={'queue_id': '123456789', 'last_event_id': -1, 'msg': '', 'result': 'success'},
+            status=200
+        )
+        responses.add(
+            responses.GET,
+            url="https://test.zulipapi.com/api/v1/events",
+            json={'result': 'success', 'msg': '', 'events': [{'id': 0}, {'id': 1}, {'id': 2}]},
+            status=200
+        )
+
+        def event_callback(x: Dict[str, Any]) -> None:
+            print(x)
+            if x['id'] == 2:
+                raise TerminationException()
+
+        client = zulip.Client(config_file="zulip/tests/test_zuliprc")
+
+        try:
+            client.call_on_each_event(
+                event_callback,
+            )
+        except TerminationException:
+            pass
+
+        try:
+            client.call_on_each_event(
+                event_callback,
+                ['message'],
+            )
+        except TerminationException:
+            pass
+
+        try:
+            client.call_on_each_event(
+                event_callback,
+                ['message'],
+                [['some', 'narrow']]
+            )
+        except TerminationException:
+            pass
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/zulip/tests/test_zuliprc b/zulip/tests/test_zuliprc
new file mode 100644
index 000000000..bffe680f4
--- /dev/null
+++ b/zulip/tests/test_zuliprc
@@ -0,0 +1,4 @@
+[api]
+email=test@zulipapi.com
+key=K1PZuAp18Cn9RFjTsf5O1HeRW6TVpyhF
+site=https://test.zulipapi.com