diff --git a/boswatch/utils/timer.py b/boswatch/utils/timer.py
index 49fb809..64cf379 100644
--- a/boswatch/utils/timer.py
+++ b/boswatch/utils/timer.py
@@ -44,25 +44,36 @@ class RepeatedTimer:
         self._event.clear()
         self._thread = Thread(target=self._target)
         self._thread.name = "RepTim(" + str(self._interval) + ")"
-        self._start = time.time()
         self._thread.start()
         logging.debug("start repeatedTimer: %s", self._thread.name)
+        return True
 
     def stop(self):
-        """!Stop the timer worker thread"""
+        """!Stop the timer worker thread
+
+        @return True or False"""
         self._event.set()
-        self._thread.join()
-        logging.debug("stop repeatedTimer: %s", self._thread.name)
+        if self._thread is not None:
+            logging.debug("stop repeatedTimer: %s", self._thread.name)
+            self._thread.join()
+            return True
+        else:
+            logging.warning("repeatedTimer always stopped")
+            return False
 
     def _target(self):
         """!Runs the target function with his arguments"""
+        self._start = time.time()
         while not self._event.wait(self.restTime):
             logging.debug("work")
             startTime = time.time()
-            self._function(*self._args, **self._kwargs)
-            time.sleep(1.5)
-            runTime = time.time() - startTime
 
+            try:
+                self._function(*self._args, **self._kwargs)
+            except:
+                logging.exception("target throws an exception")
+
+            runTime = time.time() - startTime
             if runTime < self._interval:
                 logging.debug("ready after: %0.3f sec. - next call in: %0.3f sec.", runTime, self.restTime)
             else:
diff --git a/test/test_timer.py b/test/test_timer.py
new file mode 100644
index 0000000..29161ed
--- /dev/null
+++ b/test/test_timer.py
@@ -0,0 +1,51 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+"""!
+    ____  ____  ______       __      __       __       _____
+   / __ )/ __ \/ ___/ |     / /___ _/ /______/ /_     |__  /
+  / __  / / / /\__ \| | /| / / __ `/ __/ ___/ __ \     /_ <
+ / /_/ / /_/ /___/ /| |/ |/ / /_/ / /_/ /__/ / / /   ___/ /
+/_____/\____//____/ |__/|__/\__,_/\__/\___/_/ /_/   /____/
+                German BOS Information Script
+                     by Bastian Schroll
+
+@file:        test_timer.py
+@date:        21.09.2019
+@author:      Bastian Schroll
+@description: Unittests for BOSWatch. File must be _run as "pytest" unittest
+"""
+import logging
+import time
+import pytest
+
+from boswatch.utils.timer import RepeatedTimer
+
+
+class Test_Timer:
+    """!Unittest for the timer class"""
+
+    def setup_method(self, method):
+        logging.debug("[TEST] %s.%s", type(self).__name__, method.__name__)
+
+    @staticmethod
+    def testTarget():
+        logging.debug("run testTarget")
+
+    @pytest.fixture(scope="function")
+    def useTimer(self):
+        """!Server a RepeatedTimer instance"""
+        self.testTimer = RepeatedTimer(0.5, Test_Timer.testTarget)
+        time.sleep(0.1)
+        yield 1
+
+    def test_timerStartStop(self, useTimer):
+        assert self.testTimer.start()
+        assert self.testTimer.stop()
+
+    def test_timerStopNotStarted(self, useTimer):
+        assert not self.testTimer.stop()
+
+    def test_timerRun(self, useTimer):
+        assert self.testTimer.start()
+        time.sleep(0.6)
+        assert self.testTimer.stop()