Some of our tests have been incorrect because of misunderstandings of the behaviour of various Wayland concepts (damage only applies to pending buffers, a frame callback gets fired at most once, and so on).
Fix these, and while we're at it add an explicit test for the Firefox-endlessly-spins-without-rendering-anything scenario we were kinda accidentally testing (because we were repeatedly sending frame requests without actually submitting anything).
Some of our tests have been incorrect because of misunderstandings of the behaviour of various Wayland concepts (damage only applies to pending buffers, a frame callback gets fired at most once, and so on).
Fix these, and while we're at it add an explicit test for the Firefox-endlessly-spins-without-rendering-anything scenario we were kinda accidentally testing (because we were repeatedly sending frame requests without actually submitting anything).
Closes: #292