Add Mouse::Scroll instruction to tester

[thorn132]

This adds event recording and playback for mouse::Event::WheelScrolled, supporting any ScrollDelta and merging consecutive events.

[hecrj]

I'm not convinced with the DSL. We want something easy to write for the common use case.

I think it may be worth having different instructions for vertical and horizontal scrolling (scroll 10px being the vertical one).

But let's see how the tester evolves first before expanding it further.

[thorn132]

scroll 10px being the vertical one

And maybe swipe 10px for horizontal? Should that still allow merging horizontal and vertical scrolling into one line though, e.g. scroll 10px, swipe -20px?

But let's see how the tester evolves first before expanding it further.

I.e. 'please stop opening tester PRs'? 😅

[hecrj]

And maybe swipe 10px for horizontal? Should that still allow merging horizontal and vertical scrolling into one line though, e.g. scroll 10px, swipe -20px?

I don't know. I'm not convinced. I'd have to think about it.

I.e. 'please stop opening tester PRs'? 😅

You can open them, but I won't be reviewing them until I know where I'm going with it. So, maybe in a year or so.