Some of these test cases involve :not, and thus are affected
by our now correct handling of it for change computation.
All of them are affected by the window now being visible.
Add various tests for the change flag computation that
we do in the css selector tree.
test1: Just test the basic machinery of this test
test2: Trigger every change flag at least once
test3: Test that multiple states combine as expected
test4: Test negations (known to produce wrong results)
test5: Test a complex selector (not producing the expected
output atm)
widget-factory.ui:
The real thing: widget-factory+Adwaita. Note that
this expedts to be run with GSETTINGS_BACKEND=memory
Note that test4 checks the wrong results that we currently
produce for selectors involving :not. It will have to be
updated when we fix the handling of :not. The widget-factory.ui
testcase will certainly also be affected.
