Learning a new programming language historically starts off with the
classic “Hello World” example. I've probably written a variation on that
a bazillion times. From there you take more steps into advanced parts of
the language. If you are smart, you save your example programs to refer
back to them later. But there's a better way. And that better way is to
write test cases that exercise the capabilities of the language you are
trying to learn. This also works for new libraries within a language you
are trying to learn.
The advantages of writing test cases are plentiful. It gets you writing
actual code which helps you remember, they can be usually be run easily,
they serve as an extra source of documentation about what you are trying
to do (e.g. “How do I use gsub again? Oh yeah, it's in that string
test I wrote?”) and finally writing tests is fun.
An Example
After ignoring it for way too long, I recently started trying out the
Yahoo! User Interface
Library.
It's a JavaScript library with scads of useful utilities for buidling
web applications. So, I pulled up the documentation and started writing
a tests based on what's documented. Since it's JavaScript, I used
JsUnit since
I'm used to
JUnit on the
Java side of things. And voila we have our first test:
<html>
<head>
<title>Test Yahoo</title>
<script type="text/javascript"
src="jsUnitCore.js"></script>
<script type="text/javascript"
src="yahoo.js"></script>
<script type="text/javascript">
<!--
function testIsArray() {
assertTrue(YAHOO.lang.isArray([1,2]));
}
//-->
</script>
</head>
<body>
A test document.
</body>
</html>
(I know it's very simple but I just wanted to get a feel for the first
method in the global library and type it so my brain remembered it.)
So, now I drop the test file into my test runner and here we have the
results:
Can't you just feel your brain expanding with the possibilities?
