@stryker-mutator/core
Advanced tools
@stryker-mutator/core is a mutation testing framework for JavaScript and TypeScript projects. It helps developers improve their test suites by introducing small changes (mutations) to the code and checking if the existing tests can detect these changes. If a test fails due to a mutation, it means the test suite is effective in catching potential bugs.
Mutation Testing
This code demonstrates how to set up and run mutation testing using Stryker. It configures Stryker to mutate JavaScript files in the 'src' directory, use Jest as the test runner, and generate reports in HTML and clear-text formats.
const { Stryker } = require('@stryker-mutator/core');
const stryker = new Stryker({
mutate: ['src/**/*.js'],
testRunner: 'jest',
reporters: ['html', 'clear-text'],
coverageAnalysis: 'off'
});
stryker.runMutationTest().then(() => console.log('Mutation testing completed.'));Configuration
This is a sample Stryker configuration file. It specifies which files to mutate, the test runner to use, the reporters for output, and other settings. This configuration is essential for customizing how Stryker runs mutation tests.
module.exports = {
mutate: ['src/**/*.js'],
mutator: 'javascript',
packageManager: 'npm',
reporters: ['progress', 'clear-text', 'html'],
testRunner: 'jest',
transpilers: [],
testFramework: 'jest',
coverageAnalysis: 'off'
};Humbug is a mutation testing tool for PHP. It operates similarly to Stryker by mutating code and checking the effectiveness of the test suite. Humbug is focused on PHP, providing a specialized solution for PHP developers, unlike Stryker, which targets JavaScript and TypeScript.
Professor X: For someone who hates mutants... you certainly keep some strange company. William Stryker: Oh, they serve their purpose... as long as they can be controlled.
For an introduction to mutation testing and StrykerJS features, see stryker-mutator.io.
Please follow the quickstart on the website.
For small js projects, you can try the following command:
npm install --save-dev @stryker-mutator/core
# Only for small projects:
npx stryker run
It will run stryker with default values:
npm test as your test commandlib and src directories$ npx stryker <command> [options] [configFile]
See usage on stryker-mutator.io
See our website for the list of currently supported mutators.
See configuration on stryker-mutator.io.
Stryker can also be used programmatically from nodejs. It exports 2 classes for you to use: Stryker and StrykerCli.
import { Stryker, StrykerCli } from '@stryker-mutator/core';
Both classes can be used to run Stryker. The main difference is that Stryker is a slightly more low-level approach, while StrykerCli is the straight up CLI api.
In this example you can see how to use both.
async function main() {
// Runs Stryker as if it was called directly from the cli. Not even returns a promise, it assumes to be allowed to call `process.exit`.
new StrykerCli(process.argv /* RAW argv array */ ).run();
// Runs Stryker, will not assume to be allowed to exit the process.
const stryker = new Stryker({ concurrency: 4 } /* Partial Stryker options object */ );
const mutantResults = await stryker.runMutationTest();
// mutantResults or rejected with an error.
}
Stryker is written in TypeScript, so it is recommended to use Typescript as well to get the best developer experience.
8.6.0 (2024-09-29)
FAQs
The extendable JavaScript mutation testing framework
The npm package @stryker-mutator/core receives a total of 119,956 weekly downloads. As such, @stryker-mutator/core popularity was classified as popular.
We found that @stryker-mutator/core demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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