Create a Partial Mock with Spies |

This is a companion discussion topic for the original entry at

Hi! So far the course is great. There are a couple of concepts that I can’t wrap my head around yet. In ‘Create a Partial Mock with Spies’ he says that using spies “make your tests more honest and how your program actually works” and that we should prefer spies becase we “want to work with real data as much as possible”. But how are spies doing that for us?