Fakesub.php

<?php
class MyFakeObject extends FakeObject{

	public function getSchema() {
		return array(
			'id' => null,
			'personalDetails' => new FakeObject(array(
				'firstName' => null,
				'lastName' => null
			))
		);
	}

	public function getDefaults() {
		return array_merge_recursive(
			$this->getSchema(),
			array(
				'firstName' => 'Joe'
			)
		);
	}
	
}