Testing javascript

Testing JavaScript with Jasmine

Why should we test JavaScript?

How many times have youchanged something in JavaScript

Only to break something else?

JavaScript = Production Code!

Which means, we need to treat it with respect

And, preserve the ability to

change

and refactor our JavaScript code

Without fear of breaking something

Testing is especially important when external factors can affect how our code functions

What makes a good test?

Think F.I.R.S.T

IndependentTests should not depend on each other.

RepeatableAlways the same results, regardless of environment.

Self-Validating Pass or FailNo manual evalutation.

TimelyWrite tests before production code.

Let’s look at an example.A random function for rolling a die.

What’s wrong here?

How do we normally debug JavaScript?

Let’s forget we even mentioned that…

So… we have this buggy code.

What do we do about it?

Write a failing test

Then Run the test to see it fail

SpecRunner.html

Squash the bug

Success!

Add more tests

Win!Testing = Documentation!

Remember…

When you find yourself wanting to do this.

Write a test instead!

Questions?

by Robert Greiner on Nov 29, 2011