the binary canary testing pattern

I think I just invented a new testing pattern - The Binary Canary.

Basically, I was grouping my PHPUnit tests into a test suite and I realized that my TestCase super-classes were "failing" because they had no tests in them. Obviously this is intentional - only the specific sub-classes would have tests.

I guess I could have made the TestCase super-classes abstract, but instead I added this to the highest-level TestCase class:

/*
 * global test plumbing here
 */
class Sfx_TestCase extends PHPUnit_Framework_TestCase
{
 public function setUp()
 {
  // more global test plumbing here
 }
 public function test_Binary_Canary()
 {
  $this->assertEquals(
         "Binary Canary says test plumbing is working.", 
         "Binary Canary says test plumbing is working."
        );
 }
}

My little binary canary serves two purposes:

1. It adds an "always-pass" test to each of my TestCase classes so they don't throw up any more PHPUnit warnings.


2. Because my TestCase classes set up context-specific test plumbing, the binary canary test inherited by each of them now alerts me if I screw up any of my test plumbing - and tells me the specific area.

For example:

class Sfx_Db_TestCase extends Sfx_TestCase
{
 public function setUp()
 {
  parent::setUp();
  // Db-specific test plumbing
 }
}

And:

class Sfx_Controller_TestCase extends Sfx_TestCase
{
 public function setUp()
 {
  parent::setUp();
  // Controller-specific test plumbing
 }
}

Just like the coal-miner canaries of old, this mechanism gives me a simple yes/no signal as to whether or not my test plumbing will soon kill me, and which plumbing code is the culprit.