refactor: remove material in reorderable_list_test, scroll_notification_test, scroll_physics_test, shortcuts_test, sliver_floating_header_test, snapshot_widget_test

[rkishan516]

This PR removes Material imports from reorderable_list_test, scroll_notification_test, scroll_physics_test, shortcuts_test, sliver_floating_header_test, snapshot_widget_test.

part of: #177415
depends on: #182805

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement].
• I signed the [CLA].
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is [test-exempt].
• I followed the [breaking change policy] and added [Data Driven Fixes] where supported.
• All existing and new tests are passing.

[gemini-code-assist]

Code Review

The pull request successfully removes Material library dependencies from several widget tests by replacing MaterialApp with TestWidgetsApp, Scrollbar with RawScrollbar, and Material-specific widgets like Scaffold or Checkbox with widgets-layer equivalents. The refactoring of the Drawer regression test in reorderable_list_test.dart and the Checkbox logic in shortcuts_test.dart are particularly well-handled, maintaining the test's intent while decoupling from Material. One minor improvement is suggested to use a constant for the magic hex code used for the drag handle icon to improve readability and consistency.

[gemini-code-assist]

Since you are defining constants for colors used in the tests, consider also defining a constant for the IconData used for the drag handle (hex 0xe25d). This would improve readability and avoid repeating the magic hex value and font family string in multiple places (lines 1780 and 2177).

Suggested change

	const _kRedColor = Color(0xFFFF0000);
	const _kGreenColor = Color(0xFF00FF00);
	const _kRedColor = Color(0xFFFF0000);
	const _kGreenColor = Color(0xFF00FF00);
	const _kDragHandleIconData = IconData(0xe25d, fontFamily: 'MaterialIcons');

References

1. Optimize for readability: Code is read more often than it is written. ^(link)

[gemini-code-assist]

Use the constant suggested above for the drag handle icon to improve readability.

Suggested change

	const Icon(IconData(0xe25d, fontFamily: 'MaterialIcons')),
	const Icon(_kDragHandleIconData),

[victorsanni]

+1, or similar

[gemini-code-assist]

Use the constant suggested above for the drag handle icon to improve readability.

Suggested change

	const Icon(IconData(0xe25d, fontFamily: 'MaterialIcons')),
	const Icon(_kDragHandleIconData),

[victorsanni]

+1, or similar

[victorsanni]

Are we still working with drawers?

[rkishan516]

No, we are not, I will replace with Close list or hide list.

[victorsanni]

Can you explain the numbers change?

[rkishan516]

If i am not wrong then Material Scrollbar positioned the thumb center around x=790 (800 - some internal padding) but RawScrollbar positions the thumb center closer to x=797 (800 - half the default thumb width, approximately)

[victorsanni]

Why are we now moving by positive dy instead of negative as in existing code?

[rkishan516]

The drag direction changed from - to + because we replaced Scaffold + Scrollbar with a plain RawScrollbar. The Scaffold added extra layout layers that shifted the scrollbar track's coordinate space, causing a negative drag delta to map to a positive scroll offset. Without Scaffold, the coordinate mapping is straightforward — dragging down (+dy) scrolls down i.e. increases offset, which is the natural scroll. The magnitude also changed to half because removing Scaffold altered the viewport dimensions and thus the drag-to-scroll ratio.

[victorsanni]

Why can't we use TestWidgetsApp here?

[rkishan516]

Yup, we can. Replacing.

[victorsanni]

Suggested change

	// A focusable widget that handles ActivateIntent,
	// replacing Checkbox for this widgets-layer test.
	// A focusable widget that handles ActivateIntent.

We should not specify what it is replacing, future code readers will not see a Checkbox here and will get confused. If more code changes happen here, it could be hard to find the PR that added the Checkbox in the first place. So it is just breadcrumbing to an irrelevant implementation detail, wasting developer time.

Instead we want to guarantee that the behavior reinforced by the test is preserved. As long as that is guaranteed implementation details are free to change.

[rkishan516]

Updated

[victorsanni]

Thanks for the work here!