Someone wants to test: function do_add(a, b, add) { return add(b, a); } And does something like: do_add(1, 2, add) expect(add) to be called with

Someone wants to test: function do_add(a, b, add) { return add(b, a); } And does something like: do_add(1, 2, add) expect(add) to be called with (2, 1) Then the function is changed to: function do_add(a, b, add) { return add(a, b); } Oops, broke the test. Is this a type of behavior change that you expect would break the test? Often there are many ways to correctly do something and a good test should allow any of them.