Test to ensure caching varies depending on CORS origin
Test to ensure caching varies depending on CORS origin

It could be a security disaster if caches always served the same data
to different CORS origins, because private information (e.g., to system
admins) might leak in a cache.  The "rack-cors" gem already handles
this by inserting "Vary: Origin", as is standard recommended behavior
when using CORS.  However, it's important for security, so let's
verify that caching actually varies depending on the Origin.

Signed-off-by: David A. Wheeler <9ae72d22d8b894b865a7a496af4fab6320e6abb2@dwheeler.com>

coreinfrastructure/best-practices-badge,linuxfoundation/cii-best-practices-badge,yannickmoy/cii-best-practices-badge,coreinfrastructure/best-practices-badge,yannickmoy/cii-best-practices-badge,yannickmoy/cii-best-practices-badge,linuxfoundation/cii-best-practices-badge,coreinfrastructure/best-practices-badge,coreinfrastructure/best-practices-badge,linuxfoundation/cii-best-practices-badge,yannickmoy/cii-best-practices-badge,linuxfoundation/cii-best-practices-badge