Any way to spy on an entire instance with Jasmine

Question

I have a complex javascript class that has many functions, many of which will throw exceptions if they are called outside of a production environment. I need to pass mock instances of this class to the constructor of another class in my tests, however I do not want any of the complex classes functions to actually be called. What I would like to do is have a fake object that has all the functions and properties of the complex class, but for all the functions to just be jasmine spies that do nothing.

Basically I want to be able to do

var fakeComplexClass = createFakeObject(ComplexClass);

var testInstanceOfSimpleClass = new SimpleClass( fakeComplexClass);

And be sure that if testInstanceOfSimpleClass calls any of the fakeComplexClass functions they will be spies and thus not crash my tests.

I could do something like

var fakeComplexClass = { function1() {};, function2() {}; ... } 

but there are many functions and I have a few different complex classes I need to test so just an easy way to basically spy on every single function in a class is what I need.\

Jasmine does have createSpyObj but it requires that you pass it an array of functions. I don't want to have to maintain that array in my tests if I happen to add or delete functions from the complex class so I'd like something that can just spy on every function that is there.

Thanks in advance.

Answer 1

I created a small lib, which works with jasmine-node.

usage:

    var MyClass = function (param) {
        this.initialize(param);
    };
    MyClass.prototype.initialize = function (param) {
        if (param != "expectedParam")
            throw new TypeError();
    };

    var mock1 = jasmine.createStub(MyClass, ["*"]);
    expect(mock1.constructor).toHaveBeenCalled();
    expect(mock1.initialize).not.toHaveBeenCalled();

    var mock2 = jasmine.createStub(MyClass, ["initialize"], ["expectedParam"]);
    expect(mock2.initialize).toHaveBeenCalled();
    mock2.initialize.andCallThrough();
    expect(mock2.initialize).toThrow(new TypeError());

lib:

jasmine.createStub = function (cls, methods, args) {
    if (!(cls instanceof Function))
        throw new TypeError("Invalid class param.");

    var mockClass = function () {
        this.constructor.apply(this, args || []);
    };

    mockClass.prototype = Object.create(cls.prototype);
    mockClass.prototype.constructor = cls;

    var wrap = function (method) {
        if (!mockClass.prototype[method] instanceof Function)
            throw new TypeError("Cannot mock " + method + " it's not a function.");
        jasmine.getEnv().currentSpec.spyOn(mockClass.prototype, method);
    };

    if (methods) {
        if (!(methods instanceof Array))
            methods = [methods];
        if (methods.length == 1 && methods[0] == "*")
            for (var property in mockClass.prototype) {
                if (mockClass.prototype[property] instanceof Function)
                    wrap(property);
            }
        else
            for (var i = 0; i < methods.length; ++i) {
                var method = methods[i];
                wrap(method);
            }
    }

    return new mockClass();
};

I think this row wont work with jasmine in browser, but did not test it:

jasmine.getEnv().currentSpec.spyOn(mockClass.prototype, method);

Somehow my jasmine-node does not have a jasmine.spyOn method...