[kbn-test] Jest run script should use testPathPattern to lookup config

[nickofthyme]

Summary

TLDR; Adds logic to support the jest vscode extension by reading the --testPathPattern arg for the purpose of config lookup. This enables running tests easily in the vscode jest extension.

Currently the yarn test:jest command, requires one of the following:

• A path to a test file
• A folder where tests can be found
• A --config argument pointing to one of the many jest.config.js files

The jest vscode extension does not easily support this behavior as it expects a static command to run all tests.

One option people have used is virtualfolders but this requires enumerating all possible configs. See doc.

{
  "jest.virtualFolders": [
    {
      "name": "@kbn/maps-plugin",
      "jestCommandLine": "yarn test:jest --config x-pack/platform/plugins/shared/maps/jest.config.js"
    },
    {
      "name": "@kbn/embeddable-enhanced-plugin",
      "jestCommandLine": "yarn test:jest --config x-pack/platform/plugins/shared/embeddable_enhanced/jest.config.js"
    }
  ]
}

This could be autogenerate and @managed options in .vscode/setting but this is more complicated to achieve at the moment.

Without using virtualFolders the best option is to use the jestcommandline. But this option does not allow parameterizing the command like we can with the debug launch.json config (e.g. "${jest.testNamePattern}").

The jestcommandline does however pass a few additional argument as shown below...

node scripts/jest --testLocationInResults --json --useStderr --outputFile '/var/folders/yx/ykmyj9616fn746d191gqc50m0000gn/T/jest_runner_kibana_501_2.json' --testNamePattern 'IndexPattern Data Source #getUserMessages warning messages should show different types of warning messages$' --no-coverage --reporters 'default' --reporters '/Users/nickpartridge/.vscode/extensions/orta.vscode-jest-6.4.0/out/reporter.js' --colors --watchAll=false --testPathPattern '/Users/nickpartridge/Documents/repos/kibana/x-pack/platform/plugins/shared/lens/public/datasources/form_based/form_based.test.ts

Most importantly the --testPathPattern argument. This is passed whenever the extension is ran against a directory, file or specific test. The file name is passed as unnamed argument when run on save of a file. But the current yarn test:jest command expects this as an additional unnamed argument. This PR now treats the testPathPattern as a file or directory to find the config.

Warning

This works for most cases with the most notable exception being if you were to run a directory that contained multiple jest.config.ts files. This would error just the same as calling something like...

yarn test:jest x-pack/platform/plugins/shared

Or running this from the vscode jest extension like this...

This would result in multiple configs which will not work. I think this is not a very common use case.

If we did want to address this case I think it could be solved with virtualFolders to run files grouped by their respective configs.

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 7725770

Metrics [docs]

✅ unchanged

[kibanamachine]

Starting backport for target branches: 7.17, 8.16, 8.17, 8.x

https://github.com/elastic/kibana/actions/runs/12718816148

[kibanamachine]

💔 Some backports could not be created

Status	Branch	Result
❌	7.17	Backport failed because of merge conflicts
✅	8.16
✅	8.17
✅	8.x

Note: Successful backport PRs will be merged automatically after passing CI.

Manual backport

To create the backport manually run:

node scripts/backport --pr 206341

Questions ?

Please refer to the Backport tool documentation