Test your JavaScript with focused programmer tests. Fake depedencies.

Usage no npm install needed!

<script type="module">
  import fake from 'https://cdn.skypack.dev/fake';


Current Status: This library is ready for experimental usage.

Fake Build Status

Test one thing at a time, fake the rest.


Set an expectation of a method call on an object:

var fake = require('fake')();
var object = {};

fake.expect(object, 'method');


If the last object.method() call is not present, an exception will be thrown.

Depending on your approach to TDD, you may prefer to use stubbing over mocking instead:

var fake = require('fake')();
var object = {};

var objectMethodCall = fake.stub(object, 'method');


assert.equals(objectMethodCall.calls.length, 1);


fake.expect(object, method, [times, withArgs, andReturn | andHandle])

Set up an ordered expectation. Calling any other methods controlled by fake before this expectation has been satisifed will throw an exception.

fake.expectAnytime(object, method, [times, withArgs, andReturn | andHandle])

Set up an unordered expectation. This will only throw an error if this expectation is not verified before the process exits.

fake.stub(object, method, [times, withArgs, andReturn | andHandle])

Set up an optional expectation. This is useful for pre-filling return values for functions, without caring if the function is ever called.


  • Report non-matching anytime expectations if they are the closest match
  • Move stacktrace into own module
  • Useful error reporting
  • Partial arguments matching
  • Become self-testing
  • Documentation
  • Handle fake functions being claimed by multiple fakes
  • NodeModuleScene / BrowserScriptScene?