MySQL actual field values

[ScottFreeCode]

Some mocks provide an indication of the actual data, e.g. rabbit's list of published messages. MySQL one cannot tell from the Touchstone failure whether a field didn't match and if so which, vs if there are no records.

Could MySQL be updated to query against the primary keys (preferably just looking those up automatically) and compare the fields?

(Arguably related to #38 which is seeing expected field values)