create viper mock

[plastikfan]

Need to start using mocking, in this case so we can mock out viper config. Using uber mock.

The first to know, is how to make a mock; here is the documented example (as described in mock_test.go):

mockgen -destination mock_test.go -package gomock_test -source example_test.go

• use _-mocknames to specify the interface to be mocked and the mock name, eg:

Repository=MockSensorRepository,Endpoint=MockSensorEndpoint, where Repository is the interface name and MockSensorRepository is the desired mock name

• --source specifies where the source interface is defined, eg: -source=foo.go

But actually, this doesnt clearly explain how to mock a foreign interface. I found this: codecentric.de gomock-tutorial, which may be a bit clearer, in particular:

mockgen -destination=mocks/mock_doer.go -package=mocks github.com/sgreben/testing-with-gomock/doer Doer

where:

• mocks: is the name of a package that will contain our mocks (mocks are to be created in a specific mock package)
• there are 2 non flag arguments, an import path, and a comma-separated list of symbols
• in the above example, github.com/sgreben/testing-with-gomock/doer is the import path and Doer is the symbol to be mocked

[plastikfan]

The following command generated a mock for VIperConfig (run from the repo root dir):

mockgen -destination src/assistant/mocks/mock-global-viper-config.go -package mocks -source src/assistant/configuration/global-config.go -mock_names ViperConfig=MockViperConfig

Since we want mocks to be used externally, we generate the mocks inside a mocks package, not mocks_test.

A new task co-gen-vc has been added and a go generate statement added to global-config.go