public function testAddUserPlaylistTracks()
 {
     $tracks = array('spotify:track:1id6H6vcwSB9GGv9NXh5cl', '3mqRLlD9j92BBv1ueFhJ1l');
     $options = array('position' => 0);
     $expected = json_encode(array('spotify:track:1id6H6vcwSB9GGv9NXh5cl', 'spotify:track:3mqRLlD9j92BBv1ueFhJ1l'));
     $headers = array('Authorization' => 'Bearer ' . $this->accessToken, 'Content-Type' => 'application/json');
     $return = array('status' => 201);
     $stub = $this->setupStub('POST', '/v1/users/mcgurk/playlists/0UZ0Ll4HJHR7yvURYbHJe9/tracks?position=0', $expected, $headers, $return);
     $api = new SpotifyWebAPI\SpotifyWebAPI($stub);
     $api->setAccessToken($this->accessToken);
     $response = $api->addUserPlaylistTracks('mcgurk', '0UZ0Ll4HJHR7yvURYbHJe9', $tracks, $options);
     $this->assertTrue($response);
 }