Finish writing tests for all endpoints

[jlkalberer]

I don't think that we've covered them all. We need to finish some in DeviceController as well

I also wonder if we should be using a real mocking framework instead of hacking some mocked objects..?
We could write better tests with the mocked objects like checking if functions had been called or getting rid of the serialized functions -- we can make repositories return fake data.

[jlkalberer]

You can ignore the products endpoint for now.