public function testEnsureTTLIndex()
{
$this->collection->ensureTTLIndex(array('ttlAsc' => 1, 'ttlDesc' => -1), 12000);
$indexes = $this->collection->getIndexes();
$this->assertEquals(array('ttlAsc' => 1, 'ttlDesc' => -1), $indexes[1]['key']);
$this->assertArrayHasKey('expireAfterSeconds', $indexes[1]);
$this->assertEquals(12000, $indexes[1]['expireAfterSeconds']);
}