Source
Tests configuration of the `'fields'` setting where some form fields are mapped directly to database fields (i.e. `array('field')`) and some are mapped manually (i.e. `array('form_field' => 'database_field')`) in a single mixed array.

Source

						public function testMixedFieldMapping() {
		$subject = new Form(array(
			'model' => __CLASS__,
			'fields' => array('username' => 'name', 'group'),
			'validators' => array()
		));

		$request = (object) array('data' => array(
			'username' => 'Bob', 'group' => 'editors'
		));

		$expected = array('name' => 'Bob', 'group' => 'editors');
		$this->assertEqual($expected, $subject->check($request));
	}