Investigate testing for this module

[davidjb]

Several other Nginx modules feature testing, such as:

• https://github.com/openresty/headers-more-nginx-module
• https://github.com/yaoweibin/nginx_ajp_module

and it would be good to have the Shibboleth module tested (automatically via Travis, etc) too.

[davidjb]

Also https://github.com/FRiCKLE/ngx_cache_purge uses Test::Nginx @ http://github.com/agentzh/test-nginx

[davidjb]

Tests finally sorted and working on Travis. There was an issue whereby the environment variable NGINX was being used to set versions for download in the .travis.yml. Turns out setting this environment variable prevents Nginx from daemonising itself within a script (or via prove in Test::Nginx, which runs Nginx in this way under the hood) because it makes Nginx think that it is already daemonised.

For reference, here is where the NGINX environment variable is read, and here is where Nginx considers itself already daemonised because of the NGINX environment variable.

[davidjb]

FYI: https://trac.nginx.org/nginx/ticket/900 ticket open to change the variable / log an error / document the behaviour.