public function testIsEmptyReturnsFalseIfAnyFieldIsFilled()
{
$form = new Form();
$field1 = new TestField('foo');
$field1->setData('baz');
$field2 = new TestField('bar');
$field2->setData(null);
$form->add($field1);
$form->add($field2);
$this->assertFalse($form->isEmpty());
}