feat: add no-unsettled-absence-query rule

[JMiltier]

Checks

• I have read the contributing guidelines.

Changes

1. Add no-unsettled-absence-query rule that detects absence assertions (queryBy* + .not.toBeInTheDocument() / .not.toBeVisible() / .toBeNull() / .toBeFalsy()) before the component has settled
2. Flags absence assertions inside waitFor callbacks (pass on first invocation)
3. Recognizes settling via await expressions (findBy*, waitFor, act) or getBy*/getAllBy* calls
4. Scope-aware tree-walking: await inside a nested function does not settle the outer scope
5. 37 test cases across React, Vue, Angular, DOM, and Marko
6. recommendedConfig set to false for all frameworks (opt-in only) - open to adding as warn in presets if preferred
7. Documentation: https://github.com/JMiltier/eslint-plugin-testing-library/blob/pr/no-unsettled-absence-query/docs/rules/no-unsettled-absence-query.md

Context

Closes #1237

[codecov]

Codecov Report

❌ Patch coverage is 98.91892% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.40%. Comparing base (2002150) to head (8b383b6).

Files with missing lines	Patch %	Lines
src/rules/no-unsettled-absence-query.ts	98.90%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1278      +/-   ##
==========================================
+ Coverage   97.35%   97.40%   +0.04%     
==========================================
  Files          49       50       +1     
  Lines        6020     6205     +185     
  Branches     1544     1610      +66     
==========================================
+ Hits         5861     6044     +183     
- Misses        157      159       +2     
  Partials        2        2              

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[Belco90]

@JMiltier thanks for your PR, all checks passing now! I'll try to review this during the week.

[Belco90]

I'm not sure if isAsyncUtil is the right util to use here. This helper matches both waitFor and waitForElementToBeRemoved by default, but the latter shouldn't be reported, right? It's not even mentioned in the docs, and IIRC waitForElementToBeRemoved throws an error if the first argument (the element that should be removed) is already empty (i.e. it's a settling expression on its own).

You can limit the subset of async utils checked passing a second arg to isAsyncUtil (other rules like no-wait-for-side-effects are doing this).

Additionally, mention this in the docs, and add extra tests to check the usage of waitForElementToBeRemoved is valid. Something like:

{
    code: `
    import { render, screen, waitForElementToBeRemoved } from '@testing-library/react'

    test('waitForElementToBeRemoved callback is not a waitFor', async () => {
      render(<Component />)
      await waitForElementToBeRemoved(() => screen.queryByText('loading'))
      expect(screen.queryByText('error')).not.toBeInTheDocument()
    })
    `,
  },

[Belco90]

We need a "Limitations" section to mention that some untracked helpers (custom setup, fake timers, etc) might produce false positives.

[Belco90]

I'm worried about the performance of this util because of the following issues:

1. It revisits the tree per assertion. hasSettlingExpression calls this util twice for every preceding statement of every absence assertion, resulting in O(n²) complexity.
2. It iterates over non-AST keys. Skipping only parent means that it also traverse into loc, range, comment arrays, etc. It works because those don't carry a type but it's fragile, especially in terms of maintenance.
3. It's not consistent with the rest of the rules in the repo. We have a bunch of utils to walk a subtree in node-utils. You should be able to report awaited expressions with ESLint's visitor pattern instead (take a look at https://github.com/testing-library/eslint-plugin-testing-library/blob/main/src/rules/no-await-sync-events.ts#L99 or

   eslint-plugin-testing-library/src/rules/prefer-find-by.ts

   Line 338 in 2002150

   'AwaitExpression > CallExpression'(

   for reference).

The rule implementation must be refactored to get rid of this containsNode function and let ESLint do the single pass, collect all settling nodes (AwaitExpression + expression, checking they are getQuery with the corresponding helper), then check what absence assertions must be reported at Program:exit.

[Belco90]

Let's make the error message shorter. Right now it includes the "what" + "why" + "how to fix", but with the "what" + "how to fix" should be enough. If the user wants to know more about the why, they can go to the docs to get more info.

Suggested change

	'Absence assertion on `{{queryMethod}}` appears before the component has settled. ' +
	'The element may not have rendered yet, resulting in a false positive. ' +
	'Add an `await` expression (e.g. `findBy*`, `waitFor`, `act`) or a `getBy*` call before this assertion.',
	'Absence assertion on `{{queryMethod}}` appears before the component has settled. ' +
	'Add an `await` expression (e.g. `findBy*`, `waitFor`, `act`) or a `getBy*` call before this assertion.',