diff --git a/tests/test_functions.py b/tests/test_functions.py
new file mode 100644
index 0000000..a403116
--- /dev/null
+++ b/tests/test_functions.py
@@ -0,0 +1,22 @@
+"""Test functions.py"""
+import unittest
+from unittest.mock import MagicMock
+
+from gcloud_utils import functions
+
+PROJECT = "teste1"
+ZONE = "teste2"
+
+
+class TestFunctions(unittest.TestCase):
+    def setUp(self):
+        self.functions = functions.Functions(PROJECT, ZONE)
+
+    def test_list_functions(self):
+        self.functions = MagicMock()
+        self.functions__execute_request = MagicMock()
+
+        self.functions.list_functions()
+
+        self.functions.assert_called_once()
+        self.functions__execute_request.asser_called_once()