[code coverage] Update jest config to collect more data

[dmlemeshko]

Summary

Code coverage for oss jest tests was collecting data only for files in src/plugins, so combined coverage for files with different path (e.g.src/core) was reported as 0%

Before

After

Combined jest report has slightly better numbers:

Before

https://kibana-coverage.elastic.dev/2020-11-19T10:16:00Z/jest-combined/index.html

After

https://kibana-coverage.elastic.dev/2020-11-19T16:04:07Z/jest-combined/index.html

[tylersmalley]

Any reason for not removing the specificity and instead using something like '**/*.{js,mjs,jsx,ts,tsx}',

[dmlemeshko]

Any reason for not removing the specificity and instead using something like '**/*.{js,mjs,jsx,ts,tsx}',

Hey @tylersmalley I was not sure if we really want to include every path, e.g.:

examples/

and all the stuff under

packages
src/dev
src/legacy
src/setup_node_env 
src/test_utils

If you think that we should, I propose to go with the following template:

    '**/*.{js,mjs,jsx,ts,tsx}',
    '!**/{__test__,__snapshots__,__examples__,mocks,tests,test_helpers,integration_tests,types}/**/*',
    '!**/*mock*.ts',
    '!**/*.test.ts',
    '!**/*.d.ts',
    '!**/index.{js,ts}',

[dmlemeshko]

@elasticmachine merge upstream

[dmlemeshko]

Ready for review, code coverage pipeline started o verify: https://kibana-ci.elastic.co/job/elastic+kibana+qa-research/139/

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 9e7d7f7

Metrics [docs]

✅ unchanged

History

• 💚 Build #89328 succeeded 9f9e712
• 💚 Build #89209 succeeded fb86f36
• 💚 Build #88968 succeeded ba57c75
• 💚 Build #88936 succeeded 2225bbd

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream