diff --git a/cpu_monitor.py b/cpu_monitor.py
index 543b97f..2b84c6b 100644
--- a/cpu_monitor.py
+++ b/cpu_monitor.py
@@ -27,3 +27,4 @@ def main() -> None:
 if __name__ == "__main__":
     main()
 
+# faire une fonction qui affiche hello
diff --git a/tests/test_cpu_monitor.py b/tests/test_cpu_monitor.py
new file mode 100644
index 0000000..7eca7c4
--- /dev/null
+++ b/tests/test_cpu_monitor.py
@@ -0,0 +1,15 @@
+import unittest
+
+import cpu_monitor
+
+
+class TestCpuMonitor(unittest.TestCase):
+    def test_format_line_returns_string(self):
+        line = cpu_monitor.format_line()
+        self.assertIsInstance(line, str)
+        self.assertIn("CPU:", line)
+        self.assertIn("RAM:", line)
+
+
+if __name__ == "__main__":
+    unittest.main()