public function testDelete()
{
$collection = $this->getGridFS();
$id = $this->prepareFile();
$collection->delete($id);
$newCollection = $this->getCheckDatabase()->selectCollection('fs.files');
$newChunksCollection = $this->getCheckDatabase()->selectCollection('fs.chunks');
$this->assertSame(0, $newCollection->count());
$this->assertSame(0, $newChunksCollection->count());
}