@bdd did an excellent writeup of the issue in #264. To fix this, stop relying on stable error messages between platforms and Go versions by performing a successful certigo connect in the test rather than a failed one.
I generated new ECDSA certificates for localhost using https://github.com/square/certstrap.
This splits the logic into a cli, which handles parsing command line args and
reading files, and a terminal abstraction for handling user input and ouput.
All uses of os.Exit are removed in favor of returning errors.
Overall this enables better testing and reuse of code. Previously we had to
rely on external unit testing for CLI tests, which are harder to write tests.
Mat Byczkowski