Rspec tests not passing without sleep delay

[devpixde]

I just implemented a simple basic authentication following the "getting started" instructions. In principle it works but i do not get the original rspec tests to pass.
Tests pass only if i put some strategic "sleep 0.1" calls e.g. after button clicks. What did not help is to increase rspecs default_max_wait_time, so this seems strange to me. Any idea whats wrong on my system?