hi everyone, I don't have a very high level of Javascript (at all) and it's the first time I see something like "flip(print)(4,5)" ... I don't understand what is (print), why the function is not just flip(4,5) ? Some could explain pretty please ?
The fact that there are 2 parentheses after the function is confusing to me.

For you test cases, you should use:

Test.assertEquals(actual, expected, "Failure message");