I've found containers are helpful when you want to replace one or two specific pieces in the middle of the dependency tree for testing - let's say a mock databa

I've found containers are helpful when you want to replace one or two specific pieces in the middle of the dependency tree for testing - let's say a mock database, for example. On the other hand, I've also found myself avoiding writing code which requires deep mocks like that in order to test. Functional core, imperative shell helps with that.