modular test [options] [packages...]

Search workspaces based on their name field in the package.json and test:

• Modular packages (packages with a modular field in their package.json). modular test will act as an opinionated wrapper around jest, with a predefined Modular configuration.
• Non-Modular packages (packages without a modular field in their package.json), only if they have a test script, by running yarn test on the package’s workspace.

When the [packages...] argument is empty and no selective option has been specified (ie yarn modular test), all packages will be tested. When the [packages...] argument contains one or more non-existing package name, the non-existing packages will be ignored without an error. If Modular can’t find any package to test, Modular will warn on stdout and exit with code 0.

Test order is unspecified, so don’t rely on Modular to run certain tests before others, that Modular tests will run before non-Modular tests, or that they will run sequentially unless running Modular tests with the --runinband option.

Configuration

modular/setupEnvironment.ts

This contains the setup for tests corresponding to jest.config.js#setupFiles.

modular/setupTests.ts

This contains the setup for tests corresponding to jest.config.js#setupFilesAfterEnv.

Command line options and arguments

Arguments

[packages ...]: Packages to test. Can be combined with multiple selective options (--ancestors, --descendants, --changed and --regex). Modular will pass a list of regular expressions that satisfies all options to Jest.

Test Unique Options:

These options are unique to the test command and differ to other Modular command options.

--bypass: Bypass Modular selective behavior and flags, and send all provided flags and options directly to the Jest process with Modular configuration. Useful when running modular test from IntelliJ.

--swc: Use the @swc/jest test runner instead of babel + ts-jest. Brings significant performance improvements, but ignores ts-config in favour of its own configuration file, .swcrc.

--debug: Add the --inspect-brk option to the Node.js process executing Jest to allow a debugger to be attached to the running process. For more information, see the Node.js debugging guide.

--compareBranch <branch>: Specify the comparison branch used to determine which files have changed when using the changed option. If this option is used without changed, the command will fail.

--verbose: Activate debug logging. Useful to see which packages have been selected and which regular expression and arguments have been passed to the underlying Jest process.

--regex <regexes...>: Select all the test files matching the specified regular expressions. When combined with selective options, it will run all tests matching the selective options, and tests that match the regexes provided.

Selective Options

--ancestors: Take the packages specified by the user via arguments or options and add their ancestors (i.e. the packages that have a direct or indirect dependency on them) to the test list.

--descendants: Take the packages specified by the user via arguments or options and add their descendants (i.e. the packages they directly or indirectly depend on) to the test list.

--changed: Take the packages specified by the user via arguments or options and add all the packages whose workspaces contain files that have changed, calculated comparing the current state of the git repository with the branch specified by compareBranch or, if compareBranch is not set, with the default branch.

Jest CLI Options

modular test additionally supports passing Jest CLI options to the underlying Jest process.

Configuring IntelliJ

IntelliJ and modular test aren’t compatible out of the box. To make it work, modify the IntelliJ test configuration to use modular test with the --bypass flag.

The following is an example IntelliJ Jest configuration that uses modular test:

• Jest package: absolute_repo_path/node_modules/modular_scripts

• Working directory: absolute_repo_path/

• Jest options: test --bypass

Escape Hatches

While modular test should work straight away for most projects there are some instances where it might be necessary to overwrite the default configuration provided by modular itself.

Much like react-scripts we support overriding a handful of configuration through the jest property in the root package.json

• collectCoverageFrom
• coveragePathIgnorePatterns
• coverageThreshold
• moduleNameMapper
• modulePathIgnorePatterns
• testPathIgnorePatterns
• testRunner
• transformIgnorePatterns

collectCoverageFrom

Documentation

Default: ['<rootDir>/**/src/**/*.{js,ts,tsx}', '!**/*.d.ts']

An array of glob patterns indicating a set of files for which coverage information should be collected. If a file matches the specified glob pattern, coverage information will be collected for it even if no tests exist for this file and it’s never required in the test suite.

Example:

{
  "collectCoverageFrom": [
    "**/*.{js,jsx}",
    "!**/node_modules/**",
    "!**/vendor/**"
  ]
}

coveragePathIgnorePatterns

Documentation

Default: [ '/__tests__/', '/node_modules/', 'serviceWorker.ts', ]

An array of regexp pattern strings that are matched against all file paths before executing the test. If the file path matches any of the patterns, coverage information will be skipped.

coverageThreshold

Documentation

Default: {}

This will be used to configure minimum threshold enforcement for coverage results. Thresholds can be specified as global, as a glob, and as a directory or file path. If thresholds aren’t met, jest will fail. Thresholds specified as a positive number are taken to be the minimum percentage required. Thresholds specified as a negative number represent the maximum number of uncovered entities allowed.

moduleNameMapper

Documentation

Default:

{
    '^.+\\.(css|styl|less|sass|scss|png|jpg|ttf|woff|woff2)$': 'jest-transform-stub',
    '^react-native$': 'react-native-web',
}

A map from regular expressions to module names or to arrays of module names that allow to stub out resources, like images or styles with a single module.

The moduleNameMapper is merged with the modular defaults to provide common use cases for static assets, like static assets including images, CSS and CSS-modules.

modulePathIgnorePatterns

Documentation

Default: []

An array of regexp pattern strings that are matched against all module paths before those paths are to be considered ‘visible’ to the module loader. If a given module’s path matches any of the patterns, it will not be require()-able in the test environment.

testPathIgnorePatterns

Documentation

Default: [/node_modules/]

An array of regexp pattern strings that are matched against all test paths before executing the test. If the test path matches any of the patterns, it will be skipped.

testRunner

Documentation

Default: jest-circus

This option allows the use of a custom test runner. The default is jest-circus. A custom test runner can be provided by specifying a path to a test runner implementation.

This can be used to revert to the previous jest default testRunner (jest-jasmine2) in cases where circus is not yet compatible with an older codebase.

transformIgnorePatterns

Documentation

Default: [ '[/\\\\]node_modules[/\\\\].+\\.(js|jsx|mjs|cjs|ts|tsx)$', '^.+\\.module\\.(css|sass|scss)$', ]

An array of regexp pattern strings that are matched against all source file paths before transformation. If the file path matches any of the patterns, it will not be transformed.