Mockingbird NPM

Note: this project is now deprecated and no longer maintanined

Changes were recently merged in Nodemock and therefore this fork is no longer necessary. Please refer to the new home of the Nodemock information from now on.

Mockingbird - A NodeMock fork

Mockingbird is a fork of NodeMock 0.2.17 that introduces specific capabilities that allow mocking functions to accept and return values based on functions and not just static values. These capabilities are for now (as of version 0.3.0 of Mockingbird) the only differences with NodeMock though more features are planned to be added in the future.

The documentation below is an udpated version of NodeMock's, and the names Mockingbird and NodeMock are used interchangeably.

A simple Yet Powerful Mocking Framework for NodeJs

NodeMock is aimple Yet Powerful Mocking Framework for NodeJs

NodeMock is a very simple to use mocking framework which can be used to mock functions in JavaScript objects. NodeMock creates mock methods in less code with more expressive manner

Features

Besides it's simplicity it supports following features

Does not need an existing object to create the mock
Verify arguments (we check deeply on objects and arrays to check the validity)
Allow a return to be sent
Assertion to check whether all the rules executed
Callbacks can also be executed with providing arguments
Multiple mock functions in one object
Alter a mock function later on
Method chaining allows creating mocks super easy
Fail support added when calling method that should not be called
Mock support to call a single method more than once
Repetitive support
Ignore methods from mocking behaviour
Ability to provide functions to determine valid input for mocked functions
Ability to provide functions to generate output from mocked functions

Testing

Mockingbird can be used with any testing framework. And we've used it with Nodeunit and it's a perfect match. See Examples

Install

Use npm:

npm install mockingbird

Usage

Load the Module

var mockingbird = require("mockingbird");

Creating a mock function with taking arguments and return value

var mocked = mockingbird.mock("foo").takes(10, [10, 20, 30]).returns(98);

mocked.foo(10, [10, 20, 30]); // this will return 98

mocked.foo(10); //throws execption

Creating a mock function that takes variable parameters

var mocked = mockingbird.mock("foo").takes(function(args) {
	return(args % 2 == 0) 
});
mocked.foo(4)	// works

mocked.foo(5)	// fails

Creating a mock function that takes variable parameters and returns dynamic values

var mocked = mockingbird.mock("foo").takesF(function(args) {
	return(args % 2 == 0) 
}).returnsF(function(args) {
	return(args * 2)
});
mocked.foo(4)	// returns 8

mocked.foo(5)	// fails

Creating a mock with callback support

var mocked = mockingbird.mock("foo").takes(20, function(){}).calls(1, [30, 40]);

mocked.foo(20, function(num, arr) {
	console.log(num); //prints 30
	console.log(arr); //prints 40
});

/*
	When you invoke foo() nodemock will calls the callback(sits in argument index 1 - as specified)
	with the parameters 30 and 40 respectively. 
*/

Controlling callbacks

With the asynchronous nature of NodeJS(and brower with AJAX too) it'll be great if we can control the execution of the callback in the testing environment. And ctrl() of nodemock helps that

var ctrl = {};
var mocked = mockingbird.mock('foo').takes(10, function() {}).ctrl(1, ctrl);
//where ever in your codebase
ctrl.trigger(10, 20); // you can call this as many as you want

Add multiple mock functions

var mocked = mockingbird.mock("foo").takes(10).returns(30);
mocked.foo(10); //gives 30

mocked.mock("bar").takes(true).returns(40);
mocked.bar(true); // gives 40

Assertion Support

var mocked = mockingbird.mock("foo").takes(20);
var mocked = mockingbird.mock("bar").takes(40);

mocked.foo(20);
mocked.bar(40);

//check whether what we've defined is actually executed
mocked.assert(); //returns true

Fails when calls any method in the mock object

var mocked = mockingbird.fail();
mocked.foo(); //thorws an exception
mocked.bar(); //throws an exception

Fails when calls some particular method in the mock object

var mocked = mockingbird.mock("foo").fail();
mocked.mock("bar").takes(10);
mocked.foo(); //thorws an exception
mocked.bar(10); //works perfectly

calls a single mocked method, multiple times

var mocked = mockingbird.mock("foo").takes(10, 20).times(2);

mocked.foo(10, 20);
mocked.foo(10, 20);

calls a single mocked method, multiple times with different returns

var mocked = mockingbird.mock("foo").takes(10, 20).returns(100);
mocked.mock('foo').takes(10, 20).returns(200);

mocked.foo(10, 20); //returns 100
mocked.foo(10, 20); //returns 200

mock a single method more than once

var mocked = mockingbird.mock("foo").takes(10, 20);
mocked.mock("foo").takes(20, 30);
mocked.mock("foo").takes(500);

mocked.foo(10, 20);
mocked.foo(20, 30)
mocked.foo(500);

//check whether everything has done
mocked.assert(); //returns true

reset the mock

var mocked = mockingbird.mock('foo').returns(100);
mocked.foo(); //returns 100
mocked.assert(); //returns true
	
mocked.reset();

mocked.mock('doo').returns(300);
mocked.doo(); //returns 300
mock.assert() //returns true

ignore method

Sometime we need to ignore some methods going through mocking rules. But we need to have those methods but doing nothing.

var mocked = mock.ignore('hello');
mocked.mock('foo').returns(100);

mock.foo(); //returns 100
mock.hello(); //do nothing but the method exists

mock.assert(); // return true, assert have nothing to do with ignored methods

API Documentation

Construction

Creating a object with mock function "foo":

var mocked = require('mockingbird').mock('foo');

Ater or create a new mock method and add rules to it as usual:

mocked.mock(methodName)

Rules

takes(arg1, args2, ...)

Specify arguments of the function and verify then when calling:

mocked.takes(arg1, args2, ...)

takesF(function)

As opposed to takes(), in which we can only specify static values, takesF() (note the "F" in the name to indicate that it takes a function) allows client code to provide a predicate that determines whether the mocked function should accept ("take") the value and allowing mock code to be a bit more dynamic.

The given function will be provided with a single parameter, the current parameter.

mocked.takesF(function)

takesAll()

A shorthand function that tells the mock function to accept any input.

mocked.takesAll()

returns(returnValue)

Specify the return value of the function

mocked.returns(returnValue)

returnsF(function)

Similar to takesF(), returnsF() allows to provide a function that will dynamically generate values that will be returned from mock calls. The function will be provided with the parameters that were passed to the mock call.

mocked.returnsF(function)

calls(callbackPosition, argumentsArray)

Calls a callback at the arguments in index callbackPosition with the arguments specified in the "argumentsArray"

when using this you've to define a function signature as a callback in the argument list for a callback at index 2 .takes() function will be as, mocked.takes(10, 20, function(){})

mocked.calls(callbackPosition, argumentsArray)

fail()

If calls at very begining afterword any call on the mocked objects will fail Otherwise current mock method will fails someone called that.

mocked.fail()

times(count)

We can rule the mocked method to be called multiple times with same parameters Finally we can check that using above assert method;

mocked.times(repeatCount);

reset()

Reset all the rules and mocks created. And bring mocked object into a stage when it's created

mocked.reset()

ignore()

Ignore Some methods from the mocking behaviour

mocked.ignore()

Confirm

assert()

Checks whether rules we've defined using other methods were executed. If all the rules were executed return true, otherwise false.

	mocked.assert();

assertThrows()

Same as the mocked.assert() but throws an execption if rules breaks.

mocked.assertThrows();

Reasons for the fork

A pull request was submitted to the original maintainer of NodeMock but as no response has been received yet and as these changes may be useful to other Node.js projects, the fork was released.

Roadmap

The following features are currently in the roadmap:

Allow mock functions to execute an unlimited number of times, instead of limiting it to 1 execution by default or a defined number with times()
Automatic mocking of all methods in a given object

License

The MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.