alle 4 Testfälle hinzugefügt

src/CredentialsTest.java

     public void testOne(){
     Credentials c = new Credentials("", "");
     assertNotNull(c);
+}
 
+@Test
+    public void testTwo(){
 
-}
+        Credentials c = new Credentials("hofmannol", "GERONIMO");
+        assertTrue(c.valid());
+    }
+
+    @Test
+    public void testThree(){
+
+        Credentials c = new Credentials("hofmannolli", "GERONIMOil");
+        assertFalse(c.valid());
+    }
+
+    @Test
+    public void testFour(){
 
+        Credentials c = new Credentials("hofmannoll", "GERONIMOil");
+        assertFalse(c.valid());
+    }
 
 
 }