diff --git a/.github/workflows/python-checks.yml b/.github/workflows/python-checks.yml
index ad5ad68..6ad912f 100644
--- a/.github/workflows/python-checks.yml
+++ b/.github/workflows/python-checks.yml
@@ -24,6 +24,7 @@ jobs:
         run: |
           python3 -m pip install --upgrade pip
           python3 -m pip install -r requirements.txt
+          python3 -m pip install pytest
       - name: Run flake8
         run: |
           python3 -m pip install flake8
@@ -40,3 +41,6 @@ jobs:
         run: |
           python3 -m pip install isort
           isort *.py  --check --diff
+      - name: Run pytest
+        run: |
+          pytest -vvv
diff --git a/.idea/misc.xml b/.idea/misc.xml
index daee374..3502fd0 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -3,5 +3,5 @@
   <component name="Black">
     <option name="sdkName" value="Python 3.10 (mq2anno)" />
   </component>
-  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.10 (mq2anno)" project-jdk-type="Python SDK" />
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.9 (mq2anno)" project-jdk-type="Python SDK" />
 </project>
\ No newline at end of file
diff --git a/.idea/mq2anno.iml b/.idea/mq2anno.iml
index 7ee3eda..74d515a 100644
--- a/.idea/mq2anno.iml
+++ b/.idea/mq2anno.iml
@@ -4,7 +4,7 @@
     <content url="file://$MODULE_DIR$">
       <excludeFolder url="file://$MODULE_DIR$/venv" />
     </content>
-    <orderEntry type="jdk" jdkName="Python 3.10 (mq2anno)" jdkType="Python SDK" />
+    <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
   </component>
 </module>
\ No newline at end of file
diff --git a/test_payload.py b/test_payload.py
index e69de29..a966113 100644
--- a/test_payload.py
+++ b/test_payload.py
@@ -0,0 +1,41 @@
+"""
+MQTT payload handling tests
+"""
+import json
+
+import unittest
+from unittest.mock import MagicMock, Mock, patch
+from mq2anno import on_message, Userdata
+
+
+class TestPayloadHandling(unittest.TestCase):
+    """payload handling tests"""
+
+    # pylint: disable=no-self-use
+    @patch("mq2anno.requests")
+    def test_payload_processing(self, mock_requests):
+        """
+        Verify that payload handling in on_message() works correctly for the positive case.
+        """
+        payload = json.dumps({"annotation": True, "tags": ["foo", "bar"]})
+        msg = Mock()
+        msg.payload = payload
+        msg.topic = "foo"
+        topic_cfg = {msg.topic: {"aaa": "bbb"}}
+        url = "http://localhost:8080"
+        userdata = Userdata(topic_cfg, url, {})
+
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = {
+            "userId": 1,
+            "id": 1,
+            "title": "hello",
+        }
+        mock_requests.post.return_value = mock_response
+
+        on_message(None, userdata, msg)
+
+        mock_requests.post.assert_called_once()
+        assert len(mock_requests.post.call_args) >= 1
+        assert mock_requests.post.call_args[0][0] == url + "/api/annotations"