This adds more tests to `curl_spec.rb` to increase test coverage.
This brings almost all of the methods that don't make network
requests up to 100% line and branch coverage (the exception being
some guards in `parse_curl_output` that shouldn't happen under
normal circumstances).
In the process of writing more tests for `parse_curl_response`, I
made some tweaks to remove checks for conditions that shouldn't ever
be true (e.g., `match["code"]` isn't optional, so it will be present
if `HTTP_STATUS_LINE_REGEX` matches) and to refactor some others. I
contributed this method a while back (9171eb2), so this is me coming
back to clarify some behavior.
d8125322e1