Improve VirtualizedList test for render area change with initialScrollIndex non zero#56358
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Improve VirtualizedList test for render area change with initialScrollIndex non zero#56358chicio wants to merge 3 commits into
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Maybe @Abbondanzo you can help me to import this one? Thanks 🙏 |
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@Abbondanzo has imported this pull request. If you are a Meta employee, you can view this in D100649294. |
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Thank you @Abbondanzo 🙏. Let me know if you see any problem or if we can merge 🚀 |
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@Abbondanzo can you help me to make this be merged in master? Thank you as always🙏 |
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@Abbondanzo merged this pull request in 9b966d1. |
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This pull request was successfully merged by @chicio in 9b966d1 When will my fix make it into a release? | How to file a pick request? |
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You are the best, thank you 🙏 |
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…is appended" test (#56653) Summary: This PR is a follow-up of #56358, in order to improve and VirtualizedList tests. I re-enabled the skipped test `retains batch render region when an item is appended`. With React 19, the previous approach that was using `jest.runAllTimersAsync` in this test path was unstable because the pre-update render region could still be processing updates. I adopted the same approach used in #56358 by introducing a small helper function, `advanceUntilLastCellIndexRendered`, which advances timers one step at a time and stops when the expected state is reached: `cellsAroundViewport.last === items.length - 1`. As part of this follow-up, I also aligned `advanceUntilRenderAreaChanged` to use performNextBatch for consistent stepwise timer advancement. ## Changelog: [GENERAL][FIXED] - Re-enabled VirtualizedList "retains batch render region when an item is appended" tes Pull Request resolved: #56653 Test Plan: - Ran the VirtualizedList-test.js and verified all test cases passed. - Verified test modification correctness by intentionally breaking the related snapshot and check that it is breaking/it is failing. Reviewed By: cortinico Differential Revision: D104291284 Pulled By: Abbondanzo fbshipit-source-id: e32f8707a837a1805ce130d526768228f684e3e7
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Summary:
In
VirtualizedList-test.js, the testadjusts render area with non-zero initialScrollIndexrelied on a hardcoded timerjest.advanceTimersToNextTimer(3)to wait forVirtualizedListto expand its render window wheninitialScrollIndexis passed as prop.When
initialScrollIndex> 0,VirtualizedListblocks the render area recalculation until a valid scroll event is received (pendingScrollUpdateCount). Once unblocked, a series of batchedsetTimeoutcallbacks is scheduled through_scheduleCellsToRenderUpdate(triggered from_onLayout,_onContentSizeChange, and then fromcomponentDidUpdate). Those callbacks eventually lead to updates ofcellsAroundViewport.first/lastin_updateCellsToRender.The
cellsAroundViewportproperty ofVirtualizedListdescribes the currently rendered range of item indices, including overscan items outside the visible viewport. The hardcoded magic number 3 was effectively tied to how many internal timer callbacks fired from the chain of calls above.So I replaced the fixed count (
3) with a small helper function,advanceUntilRenderAreaChanged, that advances timers one tick at a time (every time in its own act to let theVirtualizedListcomponent update) and stops as soon ascellsAroundViewportchanges.If this doesn't happened, I trigger a specific error to report that the render area did not been change as expected.
Changelog:
[GENERAL][FIXED] - Improve render area change with initialScrollIndex non zero test in VirtualizedList to avoid magic numbers timers
Test Plan:
VirtualizedList-test.jsand verified all test cases passed.