Custom dojo/topic Jasmine Matchers

SpecTopics.js

require([
    'matchers/Topics',

    'dojo/topic'

], function (
    Topics,

    dojoTopic
    ) {
    describe('matchers/Topics', function () {
        var topicName = 'custom';
        beforeEach(function () {
            jasmine.addMatchers(Topics.matchers);
        });
        describe('toHaveBeenPublished', function () {
            it('is available as a matcher', function () {
                expect('test').not.toHaveBeenPublished();
            });
            it('subscribes to topics', function () {
                Topics.listen(topicName);

                dojoTopic.publish(topicName);

                expect(topicName).toHaveBeenPublished();
            });
            it('can be used with not', function () {
                expect(topicName).not.toHaveBeenPublished();
            });
        });
        describe('toHaveBeenPublishedWith', function () {
            it('checks arguments', function () {
                var a1 = 'blah';
                var a2 = ['hello', 'world'];

                Topics.listen(topicName);

                dojoTopic.publish(topicName, a1, a2);

                expect(topicName).toHaveBeenPublishedWith(a1, a2);
            });
            it('can be used with not', function () {
                Topics.listen(topicName);

                dojoTopic.publish(topicName, 'blah');

                expect(topicName).not.toHaveBeenPublishedWith('blah2');
            });
            it('returns the most recently published arguments', function () {
                var arg = 'blah3';
                Topics.listen(topicName);

                dojoTopic.publish(topicName, 'blah');
                dojoTopic.publish(topicName, arg);

                expect(topicName).toHaveBeenPublishedWith(arg);

                dojoTopic.publish(topicName, 'hello');

                expect(topicName).not.toHaveBeenPublishedWith(arg);
            });
        });
        describe('toHaveBeenPublishedThisManyTimes', function () {
            beforeEach(function () {
                Topics.listen(topicName);

                dojoTopic.publish(topicName);
                dojoTopic.publish(topicName);
                dojoTopic.publish(topicName);
            });
            it('counts the number of times a topic was published', function () {
                expect(topicName).toHaveBeenPublishedThisManyTimes(3);
            });
            it('can be used with not', function () {
                expect(topicName).not.toHaveBeenPublishedThisManyTimes(2);
            });
        });
    });
});

Topics.js

define([
    'dojo/_base/array',
    'dojo/topic'
], function (
    array,
    topic
    ) {
    var publishes;
    var handles;

    beforeEach(function () {
        publishes = {};
        handles = [];
    });

    afterEach(function () {
        array.forEach(handles, function (hand) {
            hand.remove();
        });
    });

    return {
        listen: function (topicName) {
            handles.push(topic.subscribe(topicName, function () {
                if (!publishes[topicName]) {
                    publishes[topicName] = [arguments];
                } else {
                    publishes[topicName].push(arguments);
                }
            }));
        },
        matchers: {
            toHaveBeenPublished: function () {
                return {
                    compare: function (topicName) {
                        var result = {
                            pass: publishes[topicName] !== undefined
                        };

                        // build message
                        var msg = 'Expected topic: "' + topicName + '"';
                        if (result.pass) {
                            msg += ' not';
                        }
                        msg += ' to have been published';

                        result.message = msg;

                        return result;
                    }
                };
            },
            toHaveBeenPublishedWith: function (util, customEqualityTesters) {
                return {
                    compare: function () {
                        // need to get from arguments keyword because we don't know
                        // how many arguments will be passed
                        // this means that I'm a grown up JS dev :)
                        var topicName = arguments[0];

                        // convert to true array
                        var expectedArgs = [].slice.call(arguments);

                        // remove topicName
                        expectedArgs.splice(0, 1);

                        var actualArgs = publishes[topicName][publishes[topicName].length - 1];
                        var result = {};
                        result.pass = array.every(expectedArgs, function (a, i) {
                            return util.equals(a, actualArgs[i], customEqualityTesters);
                        });

                        // build message
                        var msg = 'Expected topic: "' + topicName + '"';
                        if (result.pass) {
                            msg += ' not';
                        }
                        msg += ' to have been called with ' + JSON.stringify(expectedArgs) +
                            ' but it was actually called with ' + JSON.stringify(actualArgs);
                        result.message = msg;

                        return result;
                    }
                };
            },
            toHaveBeenPublishedThisManyTimes: function () {
                return {
                    compare: function (topicName, expectedNumCalls) {
                        var result = {
                            pass: publishes[topicName].length === expectedNumCalls
                        };

                        var msg = 'Expected topic: "' + topicName + '"';
                        if (result.pass) {
                            msg += ' not';
                        }
                        msg += ' to have been published ' + expectedNumCalls + ' times.';
                        result.message = msg;

                        return result;
                    }
                };
            }
        }
    };
});