Flaky test case about blocksuite HOT 3 CLOSED

I have met this when tests as basic indent and unindent fails as well, and would like to give more information :)

Pic below shows when the test accidentally fails, the state of formattedJSX, which is serialized from window.store is not updated according to the last await pressShiftTab(page) (Confusing for me so far).

The callstack is: basic indent and unindent -> await assertStoreMachJSX -> expect(snapshot.trimStart(), formattedJSX).toEqual(formattedJSX);

from blocksuite.

Some findings over recent development:

• Some asserters are sensitive to mouse movement, adding await page.mouse.move(100, 100) makes it stable.
• Some consecutive operations may be merged into unexpected undo stack items. Explicitly adding page.captureSync() in the application code makes it stable.
• To investigate a flaky test, we can mark one test case as test.only, then perform npx playwright test --repeat-each=10. It's also very helpful to run pnpm test -- --debug with await page.pause() added before certain asserters.

cc @lawvs @himself65 @thorseraq

from blocksuite.

We can get reports about flaky test after #728, and we also have some examples about fixing flaky tests:

• 4904969
• 8c80989
• 294e5b3
• 7bf699c
• 6f113db

They are mostly about timeout.

Closing this issue since we plan to fix other flaky tests case-by-case.

from blocksuite.