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Willy

Willy is an assertion library designed to be simple and readable. It doesn't follow the normal BDD/TDD assertion styles, but reads more like questions.

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

describe('some test suite', function () {
    it('should do X, Y, and Z', function () {

        // Will it?
        will(true).be(true);

    });
});

Willy...

• is super easy to use
• includes a bunch of built-in tests
• makes custom tests easy
• supports promises

Keep it simple, so you can focus on your code, not your tests. Compare testing instanceof in a few different assertion libraries.

// Chai
expect(foo).to.be.an.instanceof(Foo);

// Shouldjs
foo.should.be.an.instanceOf(Foo)

// Jasmine
expect(foo).toEqual(jasmine.any(Foo));

// Willy
will(foo).beA(Foo);

Want to add to Willy's repertoire? That's easy, too.

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'