phpunit abstract class constant - class

Question

I'm trying to find a way to test a abstract class constant that must exist and match/not match a value. Example:
// to be extended by ExternalSDKClild
abstract class ExternalSDK {
const VERSION = '3.1.1.';
}
class foo extends AController {
public function init() {
if ( ExternalSDK::VERSION !== '3.1.1' ) {
throw new Exception('Wrong ExternalSDK version!');
}
$this->setExternalSDKChild(new ExternalSDKChild());
}
}
Limitations... The framework we use doesn't allow dependency injection in the init() method. (Suggestion to refactor the init() method could be the way to go...)
The unit tests and code coverage I have run, cover all but the Exception. I can't figure out a way to make the ExternalSDK::Version to be different from what it is.
All thoughts welcome

Answer 1

First, refactor the call to new into a separate method.
Second, add a method to acquire the version instead of accessing the constant directly. Class constants in PHP are compiled into the file when parsed and cannot be changed.* Since they are accessed statically, there's no way to override it without swapping in a different class declaration with the same name. The only way to do that using standard PHP is to run the test in a separate process which is very expensive.
class ExternalSDK {
const VERSION = '3.1.1';
public function getVersion() {
return static::VERSION;
}
}
class foo extends AController {
public function init() {
$sdk = $this->createSDK();
if ( $sdk->getVersion() !== '3.1.1' ) {
throw new Exception('Wrong ExternalSDK version!');
}
$this->setExternalSDKChild($sdk);
}
public function createSDK() {
return new ExternalSDKChild();
}
}
And now for the unit test.
class NewerSDK extends ExternalSDK {
const VERSION = '3.1.2';
}
/**
* #expectedException Exception
*/
function testInitFailsWhenVersionIsDifferent() {
$sdk = new NewerSDK();
$foo = $this->getMock('foo', array('createSDK'));
$foo->expects($this->once())
->method('createSDK')
->will($this->returnValue($sdk));
$foo->init();
}
*Runkit provides runkit_constant_redefine() which may work here. You'll need to catch the exception manually instead of using #expectedException so you can reset the constant back to the correct value. Or you can do it in tearDown().
function testInitFailsWhenVersionIsDifferent() {
try {
runkit_constant_redefine('ExternalSDK::VERSION', '3.1.0');
$foo = new foo();
$foo->init();
$failed = true;
}
catch (Exception $e) {
$failed = false;
}
runkit_constant_redefine('ExternalSDK::VERSION', '3.1.1');
if ($failed) {
self::fail('Failed to detect incorrect SDK version.');
}
}