karma-jasmine-matchers

karma-jasmine-matchers

A Karma plugin to inject Jasmine-Matchers for Jasmine and Jest.

What

A huge library of test matchers for a range of common use-cases, compatible with all versions of Jasmine and Jest.

Why

Custom Matchers make tests easier to read and produce relevant and useful messages when they fail.

How

By avoiding vague messages such as "expected false to be true" in favour of useful cues such as "expected 3 to be even number" and avoiding implementation noise such as expect(cycleWheels % 2 === 0).toEqual(true) in favour of simply stating that you expect(cycleWheels).toBeEvenNumber().

Sponsors

Jasmine Matchers is written using the add-matchers library. If you have some useful matchers of your own that you could share with other Jest and Jasmine users, please give it a try.

Installation

npm install karma-jasmine-matchers --save-dev

If you are using TypeScript, you might want to npm install @types/jasmine-matchers --save-dev in order to prevent your IDE from complaining about the new Matchers.

Matchers

See the following links for a full list of Matchers and Asymmetric Matchers provided.

Integration

Just include 'jasmine-matchers' in the frameworks and 'karma-jasmine-matchers'in the plugins section of your config

module.exports = function(config) {
  config.set({
    frameworks: ['jasmine', 'jasmine-matchers'],
    files: ['src/**/*.js', 'src/**/*.spec.js'],
    // also you must add it as a plugin
    plugins: ['karma-jasmine', 'karma-jasmine-matchers']
  });
};