It's a good habit. The dependencies your method calls are externally facing, the same as it's API is. Your method should follow a well rested interface for any

It's a good habit. The dependencies your method calls are externally facing, the same as it's API is. Your method should follow a well rested interface for any touches that are outside of it: * The input * The return * The side effects You should be able to test that you've fixed a bug where you're calling a dependency 100 times instead of 1 time