Test: None

test/Prak1/TriangleCheckerTest.java

     void checkTriangle_gleichseitig () {
         assertEquals(TriangleChecker.TriangleType.EQUILATERAL, TriangleChecker.checkTriangle(10, 10, 10));
     }
+    @Test
+    void checkTriangle_none() {
+        assertEquals(TriangleChecker.TriangleType.NONE, TriangleChecker.checkTriangle(-10, 0, 10));
+    }
 }