My thinking was the test should be as thorough as possible. The function being tested should return true for all four fields in the required list... If it does return correctly for the first one but not for the second, that would be missed by only testing the first one. Considering the current bug (#2165) truncates the list at the position of the field to be removed, it's clear this kind of thoroughness is required as otherwise that kind of unpredictable bug would be missed.

Clearly these tests are not essential, the framework has lasted all this time without them, but whilst this PR is not accepted there are no tests for this class and there's a fairly big bug that is in the code base - I think having thorough tests is better than no tests regardless of whether it's better to have less tests.

I think that a test should rarely if ever change, they dictate how the functionality should work. Not being thorough leaves ambiguity to the behaviour and allows edge cases to get through undetected. That means they can be less readable because they'll only need to be consulted if the tests are broken.