Custom Tests

To define new tests, use willy.define. The function should return an expression used to determine if the test passes or fails.

willy.define(function beASubstringOf() {
    return this.expected.indexOf(this.actual) > -1;
});

will('potato').beASubstringOf('Bender Bending Rodriguez');
// expected 'potato' to be a substring of 'Bender Bending Rodriguez'

Inside every test function

• this.actual is the value passed to will()
• this.expected is the optional value passed to the test

Advanced

Pass an object to willy.define to give you more options. The object's properties should be:

• fn - The function used to perform the test.
• explanation (optional) - An explanation of what you were testing. If omitted, the test's name will be converted.
• name (optional) - The name of your test. This can usually be figured out, but ocassionally you may want to be explicit.

Changing the Explanation

// providing a better explanation
willy.define({
    fn: function beASubstringOf() {
        return this.expected.indexOf(this.actual) > -1;
    },
    explanation: 'be found inside of'
});

will('potato').beASubstringOf('Bender Bending Rodriguez');
// expected 'potato' to be found inside of 'Bender Bending Rodriguez'

Changing the Name

// providing a different name
willy.define({
    fn: function () {
        return this.expected.indexOf(this.actual) > -1;
    },
    name: 'lieWithin'
});

will('potato').lieWithin('Bender Bending Rodriguez');
// expected 'potato' to lie within 'Bender Bending Rodriguez'

Bulk Definitions

If you're lazy, use willy.loadDefinitions to define multiple tests at a time.

willy.loadDefinitions({
    beASubstringOf: {
        fn: function () {
            return this.expected.indexOf(this.actual) > -1;
        },
        explanation: 'be found inside of'
    },

    lieWithin: {
        fn: function () {
            return this.expected.indexOf(this.actual) > -1;
        }
    }
});

Modularize It

For supreme laziness, keep your custom tests in a Node module.

my-tests.js

exports.beASubstringOf = {
    fn: function () {
        return this.expected.indexOf(this.actual) > -1;
    },
    explanation: 'be found inside of'
};

exports.lieWithin = {
    fn: function () {
        return this.expected.indexOf(this.actual) > -1;
    }
};

A Test Suite

var willy = require('willy'),
    will = willy.will;

willy.loadDefinitions(require('./my-tests.js'));

describe('a test suite', function () {
    it('should be pretty easy to share custom tests', function () {
        will('potato').lieWithin('Bender Bending Rodriguez');
        // expected 'potato' to lie within 'Bender Bending Rodriguez'
    });
});