Specialized testcases
Background
We already have one specialized test case (i.e. for the popup scenario). But bloating the generic logic with conditions isn't an approach that scales.
This issue came up in #144 (closed) discussions.
What to change
Split out the popup logic into test/wrappers/pages/specialized/popup.js
and change the test runner logic to check if there is a matching script in test/wrappers/pages/specialized/
that has the same filename (ignoring file extensions) as the test page, and if available run that script instead of performing the generic screenshot approach.