So you are a C# developer. And you need to read the code and understand its structure. Maybe you’ve just joined the project, or it’s your own code you wrote 1 year ago.
Dependency Inversion is one of the five principles of widely known and acknowledged S.O.L.I.D. design guidelines. This principle is very powerful and useful when applied consistently.
We use constructor dependency injection throughout our application. Most service classes have constructors, which accept all dependencies in form of interfaces. We also use TDD, which means we must write unit tests for every aspect of our code. So I want to discuss one specific aspect: guarding the constructor parameters from null values and testing this guard.
