The document discusses unit testing in Node.js, including what unit testing is, using mocks and fixtures to control the testing environment and isolate dependencies, and examples of writing unit tests using tools like Vows and NodeMock that mock objects and dependencies to make tests easier to write and run. It provides code samples demonstrating basic unit tests, using mocks, and dependency injection with fixtures.

1. Unit Testing
the regression shield

2. Unit Testing, Node.JS style
What is unit testing
“What to test”, not “how to test”
Vows, NodeMock, and CommonSense™

3. Vows
Use vows properly
Run the test suite runner BEFORE pull requests
Check confessions server AFTER pull request
integration

4. Test Suite Runner
$ bin/fo test
$ bin/fo test -v (verbose)
$ bin/fo --help (kills nyancats)
Test it out...

5. Writing a test case
Config Object
Goal:
Load contents from a config file
Parse contents and return as a JSON string
Should handle errors gracefully
See wiki/testing-example1-basic

6. Writing a test case
What’s the problem here?
1 - Depends on files
2 - Hard to setup test environment
3 - It’s NOT unit testing

7. Mocks
Control Environment
Run It Anywhere™
Mock objects to the rescue!
See wiki/testing-example2-mock

8. NodeMock
https://github.com/arunoda/nodemock
Mocking solution made easy
No need to rewrite code for every single test
context
See wiki/testing-example3-nodemock

9. NodeMock
Mocking objects in test cases are messy
How to re-use mock objects
When to re-use mock objects
When NOT to re-use mock objects

10. Fixtures
Control environment
“Clean Slate” to run tests on
No external dependencies
Injects dependencies
Used in manufacturing’s testing procedures
See wiki/testing-example4-fixtures

11. Dependency Injection
WTF is DI?
Inject dependency vs Encapsulated dependency
Constructor injection, Getter/setter injection,
Service Locator, Factory & DI Containers
Dependency Injection = Easier to test
Use FO(‘...’) to auto-construct components

12. Code Samples
Config File: http://pastebin.com/N65mt2eh
Simple Test: http://pastebin.com/Df7ysdEH
JSON File: http://pastebin.com/Qbt52Cba
With Mock: http://pastebin.com/G0812kxz
NodeMock: http://pastebin.com/swGR379h
Fixture: http://pastebin.com/f4daFf5Z

13. -Q&A-