Modify logic and add more unittest to increase code coverage

providers/resource/bin/wifi_interface_mode.py

@@ -11,7 +11,7 @@ def run_command(command: List[str]) -> str:
         )
         return result.stdout.decode("utf-8")
     except Exception as e:
-        raise SystemError("An unexpected error occurred: {}", e)
+        raise SystemError("An unexpected error occurred: {}".format(e))
 
 
 def get_interfaces() -> List[Tuple[str, str]]:
@@ -20,7 +20,7 @@ def get_interfaces() -> List[Tuple[str, str]]:
     if output:
         matches = re.findall(interface_pattern, output, re.DOTALL)
         return [(phy, interface) for phy, interface in matches]
-    return []
+    raise SystemExit(0)
 
 
 def get_wiphy_info() -> List[Tuple[str, List[str]]]:
@@ -59,9 +59,6 @@ def print_supported_modes(
 
 def main():
     interfaces = get_interfaces()
-    if not interfaces:
-        print("")
-        return
     wiphy_info = get_wiphy_info()
     print_supported_modes(interfaces, wiphy_info)
 

providers/resource/tests/test_wifi_interface_mode.py

@@ -22,9 +22,14 @@ def test_run_command_success(self, mock_run):
     @patch("subprocess.run")
     def test_run_command_failure(self, mock_run):
         mock_run.side_effect = Exception("Command failed")
-        with self.assertRaises(SystemError):
+        with self.assertRaises(SystemError) as context:
             run_command(["echo", "hello"])
 
+        self.assertIn(
+            "An unexpected error occurred: Command failed",
+            str(context.exception),
+        )
+
     @patch("wifi_interface_mode.run_command")
     def test_get_interfaces(self, mock_run_command):
         mock_run_command.return_value = """
@@ -37,6 +42,15 @@ def test_get_interfaces(self, mock_run_command):
         result = get_interfaces()
         self.assertEqual(result, expected)
 
+    @patch("wifi_interface_mode.run_command")
+    def test_get_interfaces_no_wifi_interface(self, mock_run_command):
+        mock_run_command.return_value = ""
+
+        with self.assertRaises(SystemExit) as cm:
+            get_interfaces()
+
+        self.assertEqual(cm.exception.code, 0)
+
     @patch("wifi_interface_mode.run_command")
     def test_get_wiphy_info_with_one_phy(self, mock_run_command):
         mock_run_command.return_value = """Wiphy phy0