topiarist/test/ClassFulfillsSpec.js

Topiarist provides tree and shape-based type verification for JavaScript.

'use strict';

var topiarist = require('..');
var err = require('./errorFuncs');
var expect = require('expectations');

describe('topiarist.classFulfills', function() {
	var Class, Interface;

	beforeEach(function() {
		Class = function() {};
		Interface = function() {};
	});

	it('throws an error if the class is null.', function() {
		expect( function() {
			topiarist.classFulfills(null, Interface);
		}).toThrow(err._NULL('Class', 'classFulfills'));
	});

	it('throws an error if the protocol is null.', function() {
		expect( function() {
			topiarist.classFulfills(Class, null);
		}).toThrow(err._NULL('Protocol', 'classFulfills'));
	});

	it('returns true if all functions on an interface prototype are also provided by the class.', function() {
		Interface.prototype.randomThing = function() {};
		Interface.prototype.otherThing = function() {};

		Class.prototype.randomThing = function() {};
		Class.prototype.otherThing = function() {};
		Class.prototype.nonRelevantThing = function() {};

		expect( topiarist.classFulfills(Class, Interface)).toBe(true);
	});

	it('returns false if not all functions on an interface prototype are provided by the class.', function() {
		Interface.prototype.randomThing = function() {};
		Interface.prototype.otherThing = function() {};

		Class.prototype.randomThing = function() {};

		expect( topiarist.classFulfills(Class, Interface)).toBe(false);
	});

	it('returns true if all functions on an interface prototype are inherited by the class.', function() {
		Interface.prototype.randomThing = function() {};
		Interface.prototype.otherThing = function() {};

		function Parent() {
		}
		Parent.prototype.randomThing = function() {};
		Parent.prototype.otherThing = function() {};
		Parent.prototype.nonRelevantThing = function() {};

		topiarist.extend(Class, Parent);

		expect( topiarist.classFulfills(Class, Interface)).toBe(true);
	});

	it('returns false if the protocol has properties of a different type to the class.', function() {
		Interface.prototype.randomThing = function() {};
		Interface.prototype.otherThing = 23;

		Class.prototype.randomThing = function() {};
		Class.prototype.otherThing = 'string';

		expect( topiarist.classFulfills(Class, Interface)).toBe(false);
	});

	it('returns true if the protocol has properties of the same nonfunction type to the class.', function() {
		Interface.prototype.randomThing = 'string';
		Interface.prototype.otherThing = 23;

		Class.prototype.randomThing = 'different string';
		Class.prototype.otherThing = 40;
		Class.prototype.nonRelevantThing = 90;

		expect( topiarist.classFulfills(Class, Interface)).toBe(true);
	});

	it('returns true if an adhoc protocol has properties indicating the same type as the properties on the class.', function() {
		Class.prototype.randomThing = 'different string';
		Class.prototype.otherThing = 40;
		Class.prototype.nonRelevantThing = 90;

		expect( topiarist.classFulfills(Class, {randomThing: String, otherThing: Number})).toBe(true);
	});


});