public function testDestroy() {
$collection = $this
->getMockBuilder('MongoCollection')
->disableOriginalConstructor()
->getMock();
$this->mongo
->expects($this
->once())
->method('selectCollection')
->with($this->options['database'], $this->options['collection'])
->will($this
->returnValue($collection));
$collection
->expects($this
->once())
->method('remove')
->with(array(
$this->options['id_field'] => 'foo',
));
$this
->assertTrue($this->storage
->destroy('foo'));
}