use promises in clean_playlists

Signed-off-by: Tomas Neme <lacrymology@gmail.com>
expected time into a variable for better debugging

Signed-off-by: Tomas Neme <lacrymology@gmail.com>
clean up self.playlists after test

Signed-off-by: Tomas Neme <lacrymology@gmail.com>
make sure we have a 10m long single playlist

Signed-off-by: Tomas Neme <lacrymology@gmail.com>
debug logging

Signed-off-by: Tomas Neme <lacrymology@gmail.com>