amex-jest-preset

An opinionated Jest preset

For a React specific Jest preset use: amex-jest-preset-react which extends off of this preset and adds some React specific configurations.

Want to get paid for your contributions to amex-jest-preset? Send your resume to [email protected]

Configurations

• cacheDirectory is used to let Jest know to output its cache within the project workspace (specifically in <rootDir>/.jest-cache). This is useful as it eliminates issues caused by several projects sharing the same Jest cache on CI builds.

• collectCoverage tells Jest to collect code coverage metrics on every test run

• collectCoverageFrom tells Jest what directories to collect and not collect coverage metrics from

• coverageDirectory tells Jest to output the coverage reports into the ./test-results/coverage directory

• coverageReporters tells Jest to report coverage as text which outputs to your console, cobertura format which Jenkins uses, and lcov which produces the pretty HTML you are all used to seeing from Istanbul

• coverageThreshold tells Jest to return failure unless code coverage is 100% for branch, function, line, and statement. (Yes this does mean that your build will fail if you don't have 100% code coverage)

• modulePathIgnorePatterns tells Jest to not even consider npm-cache and npm directories for module loading. This prevents issues on CI server where npm-cache may be shared across build workspaces.

• testEnvironment tells Jest to use node as its test environment. This is done for performance reasons as the full jsdom environment is not needed for most tests and including it slows Jest startup time considerably.

• testResultsProcessor is used to output test results onto our HTML report creator. That way pretty HTML test results are created in <rootDir>/test-results/

Usage

1. Install:

npm install --save-dev amex-jest-preset

2. And in your Jest configuration:

{
  "preset": "amex-jest-preset"
}

And... that's it! You now have all the boilerplate Jest configurations set up for you! Running jest from your npm test script will use all these configurations!

Extending the preset provided configuration

You can add on and/or override any values provided in this preset as you wish in your Jest configuration.

Contributing

We welcome Your interest in the American Express Open Source Community on Github. Any Contributor to any Open Source Project managed by the American Express Open Source Community must accept and sign an Agreement indicating agreement to the terms below. Except for the rights granted in this Agreement to American Express and to recipients of software distributed by American Express, You reserve all right, title, and interest, if any, in and to Your Contributions. Please fill out the Agreement.

Please feel free to open pull requests and see CONTRIBUTING.md to learn how to get started contributing.

License

Any contributions made under this project will be governed by the Apache License 2.0.

Code of Conduct

This project adheres to the American Express Community Guidelines. By participating, you are expected to honor these guidelines.