refactoring: test absolute function, rename

src/test/test_funktionen.c

@@ -32,7 +32,7 @@ void test_cubeRoot_for_27(void) {
     TEST_ASSERT_EQUAL_FLOAT(3.0, result);
 }
 
-void test_absolute(void) {
+void test_absolute_for_5(void) {
     float result = absolute(-5.0);
     TEST_ASSERT_EQUAL_FLOAT(5.0, result);
 }