When the request.remote_addr remains the default for testing, which is
0.0.0.0, the exception is simply raised inline (bystepping the regular
exception handling from rescue_action). If the request.remote_addr is
anything else, the regular rescue_action process takes place. This means
you can test your rescue_action code by setting remote_addr to something
else than 0.0.0.0.
The exception is stored in the exception accessor for further inspection.