authtest command

authtest is a diagnostic tool for implementations of the GOAUTH protocol described in https://golang.org/issue/26232.

It accepts a single URL as an argument, and executes the GOAUTH protocol to fetch and display the headers for that URL.

CAUTION: authtest logs the GOAUTH responses, which may include user credentials, to stderr. Do not post its output unless you are certain that all of the credentials involved are fake!