There are a few different approaches to testing in the spectrum between simple unit tests and complete E2E tests. If I had to choose one approach to prioritize I would pick integration tests.

The key reasons are:

• Tests a flow of multiple functions, in contrast with unit tests where only a single function is tested
• Self contained i.e. the test has no external dependencies on a deployed environment etc.
• Makes logical sense to test a complete function in a REST api, a single Lambda in AWS or an Azure function

The problem

In my case the goal was to setup a test suite for a .NET web api. I quickly realized that the naive way to explicitly instantiate every controller plus all dependencies would lead to lots of repeated boilerplate code in order to setup a test case. I also wanted to make use of the existing DI configuration.
So how to create a generic setup where new test cases is a breeze to create? 🤔