So I see a couple of false positive scenarios in this test that need to be fixed.  First `onAttach` could be called before `tab.attach({` makes the tab go back, and second `onAttach` could be called before `counter == 3`.

To fix the latter add a `assert.equal(counter, 3, 'counter is 3 in onAttach')` test in `onAttach`, and to fix the former add some variable like `let goneBack = false;` then set it to true after the `tab.attach` call to go back, and add a assert.ok for it in `onAttach`.