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 .