riveter/spec/mixin.spec.js

Mix-in, inheritance and constructor extend behavior for your JavaScript enjoyment.

/*global describe,it*/

// Support running tests directly via mocha
if (typeof riveter === "undefined") {
    var riveter = typeof window === "undefined" ? require("../lib/riveter.js") : window.riveter; //jshint ignore:line
    var expect = typeof window === "undefined" ? require("expect.js") : window.expect;
}

describe("riveter - constructor.mixin", function() {

    var mixinA = {
        greet: function() {
            return "Oh, hai " + this.name;
        }
    };

    var mixinB = {
        greet: function() {
            return "BOO! " + this.name;
        }
    };

    var mixinC = {
        sayGoodbye: function() {
            return "Buh Bye " + this.name;
        }
    };

    describe("when calling mixin with one argument", function() {
        var F2 = function(val) {
            this.name = val;
        };
        riveter(F2);
        F2.mixin(mixinA);
        var f2 = new F2("Who");

        it("should apply mixin method to the instance", function() {
            expect(f2).to.have.property("greet");
        });

        it("should produce expected mix-in behavior", function() {
            expect(f2.greet()).to.be("Oh, hai Who");
        });

        it("should apply shared/constructor methods", function() {
            expect(F2.hasOwnProperty("mixin")).to.be(true);
            expect(F2.hasOwnProperty("extend")).to.be(true);
            expect(F2.hasOwnProperty("inherits")).to.be(true);
            expect(F2.hasOwnProperty("compose")).to.be(true);
        });
    });

    describe("when calling mixin with two arguments", function() {
        var F2 = function(val) {
            this.name = val;
        };
        riveter(F2);
        F2.mixin(mixinA, mixinC);
        var f2 = new F2("Who");

        it("should apply mixin methods to the instance", function() {
            expect(f2).to.have.property("greet");
            expect(f2).to.have.property("sayGoodbye");
        });

        it("should produce expected behavior", function() {
            expect(f2.greet()).to.be("Oh, hai Who");
            expect(f2.sayGoodbye()).to.be("Buh Bye Who");
        });

        it("should apply shared/constructor methods", function() {
            expect(F2.hasOwnProperty("mixin")).to.be(true);
            expect(F2.hasOwnProperty("extend")).to.be(true);
            expect(F2.hasOwnProperty("inherits")).to.be(true);
            expect(F2.hasOwnProperty("compose")).to.be(true);
        });
    });

    describe("when mixin methods collide with prototype methods", function() {
        var F2 = function(val) {
            this.name = val;
        };
        F2.prototype.greet = function() {
            return "Hello " + this.name;
        };
        riveter(F2);
        F2.mixin(mixinA);
        var f2 = new F2("Who");

        it("mix-in should **not** patch prototype", function() {
            expect(f2.greet()).to.be("Hello Who");
        });

        it("should apply shared/constructor methods", function() {
            expect(F2.hasOwnProperty("mixin")).to.be(true);
            expect(F2.hasOwnProperty("extend")).to.be(true);
            expect(F2.hasOwnProperty("inherits")).to.be(true);
            expect(F2.hasOwnProperty("compose")).to.be(true);
        });
    });

    describe("when mixin methods collide with other mixin methods", function() {
        var F2 = function(val) {
            this.name = val;
        };
        riveter(F2);
        F2.mixin(mixinB, mixinA);
        var f2 = new F2("Who");
        it("should apply mixin method to the instance", function() {
            expect(f2).to.have.property("greet");
        });
        it("should produce expected mix-in behavior (last mixin wins)", function() {
            expect(f2.greet()).to.be("Oh, hai Who");
        });

        it("should apply shared/constructor methods", function() {
            expect(F2.hasOwnProperty("mixin")).to.be(true);
            expect(F2.hasOwnProperty("extend")).to.be(true);
            expect(F2.hasOwnProperty("inherits")).to.be(true);
            expect(F2.hasOwnProperty("compose")).to.be(true);
        });
    });

});