added unittests for file_monitor.py

tests/unittests/test_file_monitor.py

@@ -0,0 +1,58 @@
+import unittest
+from unittest.mock import patch, MagicMock
+import os
+import time
+import threading
+import BPTK_Py.logger.logger as logmod
+
+
+from BPTK_Py.modelmonitor.file_monitor import FileMonitor  # Deine Datei mit der Klasse
+
+class TestFileMonitor(unittest.TestCase):
+
+    @patch("os.path.isfile", return_value=True)  # simulates that a file exists
+    @patch("os.stat")  # mock for the timestamp
+    def test_monitor_detects_file_change(self, mock_stat, mock_isfile):
+        logmod.loglevel = "INFO"
+
+        #cleanup logfile
+        try:
+            with open(logmod.logfile, "w", encoding="UTF-8") as file:
+                pass
+        except FileNotFoundError:
+            self.fail()
+
+        # simulated timestamp
+        mock_stat.return_value.st_mtime = 100
+
+        #setup FileMonitor with mocked update function
+        mock_update_func = MagicMock()
+        updater = FileMonitor(json_file="test.json", update_func= mock_update_func)
+        updater._cached_stamp = 50  # older timestamp
+
+        # start `__monitor` as separate thread
+        monitor_thread = threading.Thread(target=updater._FileMonitor__monitor)
+        updater.running = True
+        monitor_thread.start()
+
+        # Wait and let the Thread run
+        time.sleep(2)
+
+        # stop 
+        updater.running = False
+        monitor_thread.join()
+
+        # Check if the
+        mock_update_func.assert_called_once_with("test.json")
+
+        try:
+            with open(logmod.logfile, "r", encoding="UTF-8") as file:
+                content = file.read()
+        except FileNotFoundError:
+            self.fail()
+
+        self.assertIn("[INFO] JSON Monitor: Observed a change to test.json", content)  
+        self.assertIn("[INFO] JSON Monitor for test.json: model updated and relaoded scenarios!", content)  
+
+if __name__ == "__main__":
+    unittest.main()