Code review comment for lp:~julian-edwards/gwacl/delete-container

Looks good, given the difficulties with unit-testing in Go. Maybe in addition to testing that deliberately induced errors come out as non-nil, you could also cursorily check their contents.

Use the ErrorMatches checker to verify that an error matches a given regex:

    // Don't care what else is in the error, but the original error message
    // must be in there somewhere.
    c.Check(err, ErrorMatches, ".*canned error.*")