Add test coverage for the code that parses and validates the config

[steinfletcher]

We want some coverage on the config parsing code. Currently the apitests define the config as structs, which is post validation in the code. We could either

1. Unit test the file/config.go code
2. Define the config as json in the apitest, which means apitests tests cover config parsing and validation

My preference is for 2 but I am open to suggestions.