Add tools/test-lib.

This starts to add direct test coverage on
zulip_bots/zulip_bots/lib.py.

It is not yet integrated into tools/test-main.

zulip_bots/zulip_bots/lib_tests.py

@@ -0,0 +1,60 @@
+from unittest import TestCase
+from zulip_bots.lib import (
+    ExternalBotHandler,
+    StateHandler,
+)
+
+class FakeClient:
+    def __init__(self):
+        self.storage = dict()
+
+    def get_profile(self):
+        return dict(
+            user_id='alice',
+            full_name='Alice',
+            email='alice@example.com',
+        )
+
+    def update_storage(self, payload):
+        new_data = payload['storage']
+        self.storage.update(new_data)
+
+        return dict(
+            result='success',
+        )
+
+    def get_storage(self):
+        return dict(
+            result='success',
+            storage=self.storage,
+        )
+
+    def send_message(self, message):
+        pass
+
+class LibTest(TestCase):
+    def test_basics(self):
+        client = FakeClient()
+
+        handler = ExternalBotHandler(
+            client=client,
+            root_dir=None,
+            bot_details=None,
+            bot_config_file=None
+        )
+
+        message = None
+        handler.send_message(message)
+
+    def test_state_handler(self):
+        client = FakeClient()
+
+        state_handler = StateHandler(client)
+        state_handler.put('key', [1, 2, 3])
+        val = state_handler.get('key')
+        self.assertEqual(val, [1, 2, 3])
+
+        # force us to get non-cached values
+        state_handler = StateHandler(client)
+        val = state_handler.get('key')
+        self.assertEqual(val, [1, 2, 3])