Allow adding code for tests that's not compiled for releases

[ashmrtn]

Mocks and other code meant specifically for testing should not be compiled into binaries or production code. However, adding helper functions to _test.go files means it cannot be used in other packages which leads to either code duplication or compiling the code all the time. It also runs the risk of production code coming to depend on "test" code without realizing it

We should come up with some system (build tags, make rules, or something else) to ensure this sort of code is only available for testing

[ryanfkeepers]

Are we currently building test code into the release binary?

[ashmrtn]

mockconnector may be getting compiled in. I can't say I've actually checked