diff --git a/tests/test_http.sh b/tests/test_http.sh
index 005f00b924..bada74c22f 100755
--- a/tests/test_http.sh
+++ b/tests/test_http.sh
@@ -71,7 +71,7 @@ username = testadmin
 password = password
 _EOF_
 
-        rlRun -t -c "./tests/test_utf8_uploads.py -v"
+        rlRun -t -c "PYTHONPATH=../Kiwi ./tests/test_utf8_uploads.py -v"
     rlPhaseEnd
 
     rlPhaseStartTest "Should send ETag header"
diff --git a/tests/test_utf8_uploads.py b/tests/test_utf8_uploads.py
index 35f7c35444..6c173d853e 100755
--- a/tests/test_utf8_uploads.py
+++ b/tests/test_utf8_uploads.py
@@ -1,16 +1,19 @@
 #!/usr/bin/env python3
 
 #
-# Copyright (c) 2022 Kiwi TCMS project. All rights reserved.
+# Copyright (c) 2022-2023 Kiwi TCMS project. All rights reserved.
 # Author: Alexander Todorov <info@kiwitcms.org>
 #
 
+import base64
 import ssl
+import tempfile
 import unittest
 from unittest.mock import patch
 
 import requests
 from tcms_api import TCMS
+from tcms.settings.common import FILE_UPLOAD_MAX_SIZE
 
 try:
     _create_unverified_https_context = ssl._create_unverified_context
@@ -29,14 +32,37 @@ def get(self, url, **kwargs):
 
 
 class Utf8UploadTestCase(unittest.TestCase):
+    @staticmethod
+    def create_file(size, name):
+        """
+        Create a temporary file with specific size.
+        """
+        (_handle, file_name) = tempfile.mkstemp(prefix=f"kiwitcms-test-{name}.")
+        with open(file_name, "wb") as file:
+            for _ in range(size):
+                file.write("T")
+
+        return file_name
+
+    def b64_file(self, size, name):
+        """
+        Create a temporary file and return it's contents in Base64,
+        which can be passed directly to rpc.User.add_attachment().
+        """
+        file_name = self.create_file(size, name)
+        with open(file_name, "rb") as file_handle:
+            file_content = file_handle.read()
+            file_content = base64.b64encode(file_content).decode()
+            return (file_name, file_content)
+
     @classmethod
     def setUpClass(cls):
         with patch("requests.sessions.Session") as session:
             session.return_value = DoNotVerifySSLSession()
             cls.rpc = TCMS().exec
 
-    def upload_and_assert(self, filename):
-        result = self.rpc.User.add_attachment(filename, "a2l3aXRjbXM=")
+    def upload_and_assert(self, filename, contents="a2l3aXRjbXM="):
+        result = self.rpc.User.add_attachment(filename, contents)
         self.assertIn("url", result)
         self.assertIn("filename", result)
 
@@ -46,6 +72,17 @@ def test_with_filename_in_french(self):
     def test_with_filename_in_bulgarian(self):
         self.upload_and_assert("Screenshot_2021-12-07 Плащане.png")
 
+    def test_uploading_file_with_maximum_allowed_size_should_work(self):
+        file_name, file_content = self.b64_file(FILE_UPLOAD_MAX_SIZE, "5mb-file")
+        self.upload_and_assert(file_name, file_content)
+
+    def test_uploading_file_with_size_greater_than_maximum_should_fail(self):
+        file_name, file_content = self.b64_file(FILE_UPLOAD_MAX_SIZE + 1, "file-gt-5mb")
+        # fixme: this should fail
+        result = self.rpc.User.add_attachment(file_name, file_content)
+        self.assertIn("url", result)
+        self.assertIn("filename", result)
+
 
 if __name__ == "__main__":
     unittest.main()