Testing JavaScript

with Jasmine

Why should we test JavaScript?

How many times have you changed 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

fix

clean

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

Fast

Independent

Tests should not depend on each other.

Repeatable

Always the same results, regardless of environment.

Self-Validating

Pass or FailNo manual evalutation.

Timely

Write 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?