[6.x] Remove negative assertions from TestCase

[duncanmcclean]

This pull request removes negative assertions from our TestCase and the AddonTestCase to workaround the assert($count >= 0) error after a recent PHPUnit change.

I can't see any issues with removing them - apart from a warning from a test calling expectNotToPerformAssertions(). I've removed the expectation for now as I'm not sure how it relates to the purpose of the test. Feel free to add back if you think its necessary.

[jasonvarga]

I can't see any issues with removing them

The assertion counts would be wrong.

e.g. if you have a test like

function test_foo() {
  // blank
}

PHPUnit should warn you that you have no assertions. The mock in the base test case would add to that count, so it would say 1 assertion even if you had none. So we added the negative to counter that.

We added this wangjangling of expectations and assertion counts for earlier versions of Mockery/PHPUnit/etc. I think we can do away with it now. See #6689

[jasonvarga]

Then that test that had $this->expectNotToPerformAssertions();... well, I'm not sure why that was there. Maybe expectException didn't actually add an assertion once upon a time? Anyway, looks good to just remove it.