public function testUncallableFilter()
{
$subject = new Form(array('model' => __CLASS__, 'filters' => array('username' => true)));
$request = (object) array('data' => array('username' => 'Test'));
$expected = 'Authentication filter for `username` is not callable.';
$this->assertException($expected, function () use($subject, $request) {
$subject->check($request);
});
}