test PSGI programs using WWW::Mechanize

 PSGI is a specification to decouple web server environments from web
 application framework code.
 .
 Test::WWW::Mechanize is a subclass of WWW::Mechanize that incorporates
 features for web application testing. The Test::WWW::Mechanize::PSGI
 module meshes the two to allow easy testing of PSGI applications.