[bevy_ui/layout] Add tests, missing asserts, and missing debug fields for UiSurface

[StrikeForceZero]

This is 3 of 5 iterative PR's that affect bevy_ui/layout

• Blocked by [bevy_ui/layout] Extract UiSurface to its own file #12801
• Blocked by [bevy_ui/layout] Update tests to get GlobalTransform properly #12802

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Objective

• Add tests to UiSurface
• Add missing asserts in _assert_send_sync_ui_surface_impl_safe
• Add missing Debug field print for camera_entity_to_taffy

Solution

• Adds tests to UiSurface
• Adds missing asserts in _assert_send_sync_ui_surface_impl_safe
• Adds missing impl Debug field print for camera_entity_to_taffy

[StrikeForceZero]

For now, I've excluded the one test, test_compute_camera_layout, when bevy_text is active inside layout/ui_surface::tests.
For coverage of those new bevy_text params, I went with the path of least resistance by adding the test inside layout/mod::tests since it already has a Bevy app being created.

But I'm not sure I like layout/mod owning responsibility for layout/ui_surface. Since that was the whole point of extracting ui_surface to its own file; Any suggestions? The one thing that comes to mind would be moving setup_ui_test_world to a pub mod tests {} and exposing it as pub for ui_surface to call

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I removed the change described as "Widen children param in update_children (required for tests)" because the new GhostNode changes rely on it continuing to be an iterator, and my previous reasoning is likely flawed.

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Previously I was using

const TEST_LAYOUT_CONTEXT: LayoutContext = LayoutContext {
    scale_factor: 1.0, // default 1.0
    physical_size: bevy_math::Vec2::ONE, // default Vec2(0,0)
    min_size: 0.0, // default 0.0
    max_size: 1.0, // default 0.0
};

but changed to using LayoutContext::default(). Does anyone know if the default values nullify the usefulness of the tests? They still seem to pass, but it's been several months since I initially worked on this, so I'm not acutely aware of any side effects.

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Otherwise, the only outstanding item is this discussion: #12803 (comment)

[UkoeHB]

Does anyone know if the default values nullify the usefulness of the tests?

I have not looked at the tests in detail, but the default LayoutContext has zero size, so presumably there is a lot of short-circuiting inside the layout algorithm which probably invalidates the test results. I'd revert back to using TEST_LAYOUT_CONTEXT but use a larger max_size, more like 1000.0.

[StrikeForceZero]

I'd revert back to using TEST_LAYOUT_CONTEXT but use a larger max_size, more like 1000.0.

Good idea, restored in 03c2f34

[alice-i-cecile]

Thanks for your patience <3 Really nice stuff.

[alice-i-cecile]

@StrikeForceZero this needs to be manually updated to reflect the changes on main. Sorry :( I really like this work and would love to get it in though, so please let us know if you're interested in completing this.

[StrikeForceZero]

@StrikeForceZero this needs to be manually updated to reflect the changes on main.

Ok, should be good now @alice-i-cecile