Adding in some tests of the error conditions.
Adding in some tests of the error conditions.

I don't know how to test all of them, unfortunately, so the coverage here is less than optimal.
Help figuring this out would be very welcome.

msuvajac/cpr,SuperV1234/cpr,SuperV1234/cpr,whoshuu/cpr,whoshuu/cpr,SuperV1234/cpr,msuvajac/cpr,whoshuu/cpr,msuvajac/cpr