Catch PHP warnings and notices when unit testing

PHP is great at not telling you if you do something wrong, and that usually comes back to bite you. This holds even when writing proper unit tests, because warnings and notices are separete from the exception mechanism in PHP, and so at least PHPUnit wont catch them.

But another PHP rule holds here too: there's usually a hack-ish workaround :) Just use a custom error handler such as the following, which throws exceptions for notices, warnings and other "non-exceptional" errors in PHP:

public function setUp() {
    set_error_handler(function($errno, $errstr, $errfile, $errline) {
        throw new RuntimeException($errstr . " on line " . $errline . " in file " . $errfile);
    });
}

public function tearDown() {
    restore_error_handler();
}

And thats it, for PHPUnit:

Of course your unit testing framework must support setUp and tearDown methods, and you might need to modify the snippet to work with your setup.

Happy testing!