testdouble.js

Welcome! Are you writing JavaScript tests and in the market for a mocking library to fake out real things for you? testdouble.js is an opinionated, carefully-designed test double library maintained by, oddly enough, a software agency that's also named Test Double.

If you practice test-driven development, testdouble.js was designed to promote terse, clear, and easy-to-understand tests. There's an awful lot to cover, so please take some time and enjoy our documentation, which itself is designed to show you how to make the most out of test doubles in your tests.

Docs

All of our docs are in the docs/ directory inside this repository and numbered for easy reading in the priority-order we anticipate people needing them. Here's a rough outline:

1. Installation
2. for Node.js
3. for browsers
4. initial configuration
5. Purpose of testdouble.js
6. in unit tests
7. in integration tests
8. Getting started tutorial
9. Creating test doubles
10. test double functions with td.function()
11. test double objects with td.object() 1. objects that mirror a constructor function 2. objects that mirror an object of functions 3. object of functions for an array of names 4. object of any functions using ES2015 Proxy
12. Stubbing responses
13. td.when() API
14. equality argument matching
15. one-liner stubbings
16. stubbing sequential return values
17. argument matchers 1. td.matchers.anything() 2. td.matchers.isA() 3. td.matchers.contains()
    1. matching strings
    2. matching arrays
    3. matching objects 4. td.matchers.argThat()
18. Configuring stubbings 1. ignoreExtraArgs 2. times
19. Verifying invocations
20. td.verify() API
21. equality argument matching
22. argument matchers 1. td.matchers.anything() 2. td.matchers.isA() 3. td.matchers.contains()
    1. matching strings
    2. matching arrays
    3. matching objects 4. td.matchers.argThat()
23. Argument captors
24. Configuring verifications 1. ignoreExtraArgs 2. times
25. Replacing dependencies with test doubles
26. for Node.js 1. td.replace() API
    1. Replacing plain functions
    2. Replacing plain objects
    3. Replacing a constructor function
    4. Replacing a module that doesn't exist (yet)
27. for Browser JS
28. Writing custom argument matchers
29. Debugging with testdouble.js
30. td.explain() API
31. Plugins
32. testdouble-chai
33. testdouble-jasmine
34. Frequently Asked Questions
35. Why doesn't td.replace() work with external CommonJS modules?