Jeremy Harris

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Aug 2010

Testing Quirks

In my travels across the desert plains that are unit tests, I've discovered a few quirks I thought I'd share here.

Equal !== Identical

The above is obivous, but because my testing knowledge started with the CakePHP docs and the included tests that came with the software, I wrote most of my tests using assertEqual and thought it would be sufficient. I pulled some data, sorted it, and asserted it. Pass!

But wait, I debugged the code and it doesn't match! What gives? Well, it's assertEqual. When you assert the following:

$this->assertEqual(true, array(2));

You'll find that it passes. Well, in PHP, the following is true:

true == array(2);

assertEqual uses the equal operator (which makes sense but it didn't occur to me at the time), while assertIdentical uses the identical operator (===). Things like this pass when I didn't expect them to.

$arr = array(1, 3, 2);
$result = sort($arr);
$expected = array(1, 2, 3);
$this->assertEqual($result, $expected);

This is a stupid programming language mixup on my part. sort() returns a boolean instead of the sorted array (like it would in some other languages). Then the equal assertion passes as true == array(1,2,3). So, use assertIdentical instead. It'll fail because a boolean doesn't equal the array.

$arr = array(1, 3, 2);
$result = $arr;
$expected = array(1, 2, 3);
$this->assertIdentical($result, $expected);

The above will pass using with the assertion we actually attended.

setReturnValue Once And Only Once

I've been trying out setReturnValue for testing some permissions here and there. I've found that it can only be set once. According to the SimpleTest docs, to set it more than once you'll need setReturnValueAt.

What if I don't know the number of times a function will be executed? -or- What if I just want to change it permanently for the time being?

Tough luck. Hopefully the move to PHP unit will address some of these issues. I suppose I should start reading up on those docs.

Lesson Learned

Read up on all the docs for SimpleTest and, if you're me, stop mixing up your languages.

Jeremy Harris is a web developer with over 10 years of experience. He's coded in many languages and currently focuses on PHP, both agnostic and framework-based. When he isn't at the keyboard, you can find him walking @riverthepuppy or brewing beer. He only talks in the third person when peer pressure dictates he should, such as on his blog.