Testing JavaScript

Testing JavaScript XP Methodologies

Garrett Smith Front End Engineer

What is Testing?• Testing verifies that the system does

what its supposed to

Quality

• Internal Quality - measured by the programmer

• External Quality - measured by the customer

Types of Testing• Unit Testing

• Acceptance Testing

• Internal Quality - is it easy to maintain? How hard is it to make changes?

• External Quality - does it do what it's supposed to?

Unit Testing• A "unit" can be an ADT, an Object, or a

function

Costs of not Testing• Code debt

• Can’t refactor safely

Benefits• Tests facilitate change

• Good coverage ensures that all code paths work

• Tests make the code easier to understand

• Testability leads to cleaner code; microformats

Cost of Testing• Hard work and discipline

• Requires hardcore team commitment

Freedom to ChangeTests facilitate change

OK

Fixing Bugs

Test Case• Set of independent tests

• http://dhtmlkitchen.com/ape/test/tests/dom/style-f-test.html

• setUp, tearDown, template

Test Suite• APE JavaScript Library

• http://dhtmlkitchen.com/ape/test/tests/suite.html

Tools

• JSUnit

• YUI Test

• JSCoverage

Further Reading• Agile Software Development: Principles, Patterns and Practices, Robert

C. Martin

• Architecture is a Second Order Effect, http://blog.objectmentor.com/articles/2007/10/20/architecture-is-a-second-order-effect

• Re: Simples Rules make creating Big Balls of Mud impossible. http://coding.derkeiler.com/Archive/General/comp.object/2007-01/msg00241.html

• http://en.wikipedia.org/wiki/Code_coverage

• http://www.objectmentor.com/omSolutions/agile_xp_differences.html

• Extreme programming explained: Embrace Change By Kent Beck

• Planning Extreme Programming, Beck, Fowler, Kohnke