Code review comment for lp:~cprov/adt-cloud-worker/selftest

Paul, Joe,

Thanks for the review.

I've updated the README as suggested and proposed a new change for the test_proxy checks, actually check access we depend on in production. Since they are only 3 and tend to be gone once the sources get fixed, we can make the test reflect the exact conditions we expect in production, i.e. when the test fails we know what will be broken and can act accordingly.