Testception

Most people test their custom Jasmine matchers by setting up test suite with mock data. The matcher is used with the mock data and if the matcher is implemented correctly, no test fails.

it('should pass when the actual and expected are equal', function () {
  expect({}).toEqual({});
});

However, with this approach, the cases where the matcher fails are not covered. The trivial way to do this is to prepend .not to the matcher. Still the generated error messages for a failing test are not verified.

Therefore, you need to test a matcher by testing the matcher function itself. This a already done with the matchers of Jasmine itself.

This DSL helps you with testing Jasmine 1 and 2 matchers by just using one statement.

Installing

npm install testception --save-dev or bower install testception --save-dev

Include dist/testception.min.js file in the files list of your test runner config file. Testception only has an addMatchers method which is available on the global testception variable.

If you prefer CommonJS, you could require testception by calling var testception = require('testception'); Last but not least, testception is available as an ES6 module: import {addMatchers} from 'testception';

Documentation

First of all, you need the matcher in your test file. This is the object that is passed to Jasmine's addMatchers method. It is the matcher in addMatchers({ matcherName: matcher }).

Then test the matcher by using the DSL:

// Test subject is a custom toEqual matcher
var test = expectMatcher(matcher)
  .withActual({})
  .andExpected({})
  .toPass()
  .withMessage('Expected Object({  }) not to equal Object({  })');

expectMatcher(matcher)
  .withActual({})
  .andExpected('')
  .toFail()
  .withMessage('Expected Object({  }) to equal \'\'');

Modify your test and rerun it:

test
  .withActual([])
  .andExpected([])
  .withSameMessage();

Testception expects your matcher to be a Jasmine 2 matcher by default. When you want to test a Jasmine 1 matcher, call:

expectMatcher.jasmineVersion = 1;

TODO

• Injecting util and customEqualityTesters in tested matcher
• Test custom negative comparators

Development

• npm install
• bower install

Run grunt -h to see available tasks.