Components: Use real timers where possible #47056
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
tyxla
added
[Type] Enhancement
tyxla
requested review from
Mamaduka,
mirka,
jsnajdr,
ciampo,
flootr,
chad1008,
ntsekouras and
brookewp
|
Size Change: +45 B (0%) Total Size: 1.33 MB
ℹ️ View Unchanged
|
|
Flaky tests detected in 8e64eb4. 🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/3901901345
|
I think we only prefer real times because of the bug @jsnajdr discovered. How does this affect JS Unit test runtime? But the difference probably won't be too big. |
jsnajdr
approved these changes
Jan 11, 2023
| jest.advanceTimersByTime( ms + 1 ); | ||
| return promise; | ||
| }; | ||
| const sleep = ( ms ) => new Promise( ( resolve ) => setTimeout( resolve, ms ) ); |
There was a problem hiding this comment.
This should probably get replaced with something like:
await waitFor( () => expect( onChange ).toHaveBeenCalled() );at all the places where sleep() is used.
There was a problem hiding this comment.
Thanks for the suggestion, done in 8e64eb4
There was a problem hiding this comment.
There are still the "we need to sleep for at least 1ms" comments that no longer make any sense.
There was a problem hiding this comment.
I mean, they make sense IMHO but I'm happy to remove them.
There was a problem hiding this comment.
You're right, now I realize the actually do make sense. I apologize for being so blunt.
There was a problem hiding this comment.
No worries. I think you have a point that the waitFor() calls should be self-explanatory, making the comment redundant.
There are also other, semi-philosophical but IMO very good reasons to prefer real timers when working with React Testing Library. Here I'm posting publicly what was originally an internal P2 comment in a discussion about Tumblr, but it applies universally: https://jsnajdr.wordpress.com/2023/01/11/prefer-jest-real-timers-when-testing-with-react-testing-library/ |
|
Thanks for sharing, @jsnajdr 🙇 |
|
Thank you all for working on this, and special thanks to @jsnajdr for sharing his detailed post re. fake vs real timers 👏 |
This was referenced Jan 17, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
What?
This PR updates component tests to use real timers where possible. This is a follow-up to #46714.
Why?
We discovered that Jest real timers are preferable when their use is possible, see facebook/react#25889 and the description in #46714.
How?
We're removing the specific
jest.useFakeTimers();calls, and the unnecessaryadvanceTimers: jest.advanceTimersByTimein the user-event setup. We're also removing the now unnecessaryjest.advanceTimersByTime()calls and post-test cleanup that we've been doing withjest.runOnlyPendingTimers()andjest.useRealTimers().Testing Instructions
Verify all tests still pass.
Testing Instructions for Keyboard
None
Screenshots or screencast
None.