refactoring: test_maximum_for_5_and_9 rename

src/test/test_funktionen.c

@@ -69,7 +69,7 @@ void test_absoluteDifference(void) {
     TEST_ASSERT_FLOAT_WITHIN(0.000001, 3.5, result);
 }
 
-void test_maximum(void) {
+void test_maximum_for_5_and_9(void) {
     float result = maximum(5.0, 9.0);
     TEST_ASSERT_FLOAT_WITHIN(0.000001, 9.0, result);
 }