Test successful

stringCalculator.py

@@ -35,6 +35,11 @@ class StringCalculator(IStringCalculator):
         for num in list:
             if "." in num:
                 return "only integers allowed"
+            
+            try:
+                int(num.strip())
+            except ValueError:
+                return "only integers allowed"
 
         '''Konvertirung von Strings zu Integer'''
         result = 0
@@ -72,5 +77,9 @@ class TestStringCalculator(unittest.TestCase):
         res = self.c.add("3.5")
         self.assertEqual(res, "only integers allowed")
 
+    def test_handleLetter(self):
+        res = self.c.add("1, z")
+        self.assertEqual(res, "only integers allowed")
+
 if __name__ == "__main__":
     unittest.main()
\ No newline at end of file