1.
Agile JavaScript Testing
Making the web a better place

2.
What?
TDD is...

3.
A Design Method

4.
For better quality
And less bugs

5.
It Goes like this:

6.
1. Think:
What is this code supposed to do?
How am I going to interact with it?
What would be the simplest, clearest API?

7.
2. Write a test
Test what the code is supposed to do

8.
3. Run the test
It will fail.

9.
4. Write the code
Make the test pass

10.
Repeat...

11.
Confused?

12.
“Don’t tests come after?”

13.
Terminology issues...
“tests”, “assertions”, etc...

14.
Get the words right
(it’s easier to think)

15.
Behavior Driven Development
same thing, better terminology

16.
In BDD
you write “specs” to describe “behavior”
you describe what you “expect” to occur

17.
It’s more like...

18.
Behavior Driven Development
With Screw.Unit, a BDD framework for JS
http://github.com/nkallen/screw-unit

19.
Oversimplified Example
We need a method of doubling a number

20.
First in plain text
describe doubleIt
- it returns twice the number passed to it

21.
Now with Screw.Unit

22.
What do we expect?

23.
Now run the spec

24.
Define doubleIt

25.
Run the spec again

26.
You want 4?! Done!

27.
Run the spec again

28.
A couple more expectations

29.
Run the spec again

30.
Refactor the code

31.
Run the spec again

32.
One expectation per spec
Recommended, not always necessary.
Just be pragmatic.

33.
Refactor the specs

34.
Run the spec again

35.
Before / After
Setup and teardown

36.
Higher level - UI interactions

37.
Testing the DOM
Verify JS is doing what we expect to the HTMLs

38.
Testing the DOM
In suite.html (container file), have a special DOM node:
In a before block, set it to it’s default state:

39.
Testing the DOM
In your specs, you can interact with it:

40.
Always more to explore...
Mocking and Stubbing - using the Smoke library
Testing / simulating browser events
Testing / mocking ajax requests and callbacks

41.
Integrate with your workflow
An example using Blue Ridge for Ruby on Rails

42.
Blue Ridge
A JavaScript Testing plugin for Rails
Run JavaScript tests via the command-line, with a
head-less browser environment
Uses Rhino - a Java based JavaScript interpreter
And env.js - an implementation of the DOM in pure
JavaScript (thanks John Resig!)
Screw.Unit and Smoke built in! Plus generators.
http://github.com/relevance/blue-ridge

43.
Always be testing
Run your JS tests at the same time as your
other tests!
Example...

44.
A universe of browsers
each with its own “features” (bugs)

45.
JS Test Driver
Parallel cross-browser testing via command line

46.
JS Test Driver
http://code.google.com/p/js-test-driver/
Launch the server
Capture one or more browsers
Write tests and code
Run your tests
Bonus: Continously run tests, whenever files change

47.
Future / Other
Test Swarm: Distributed Continous Integration for JS
http://testswarm.com
JSpec: An alternative BDD framework for JS
http://visionmedia.github.com/jspec

48.
Thanks!
Scott Becker
becker.scott@gmail.com
http://synthesis.sbecker.net