Move your logic to pure functions. Use classes for plumbing. Now you can unit test the logic, and integration test the plumbing. You can easily test with a real

Move your logic to pure functions. Use classes for plumbing. Now you can unit test the logic, and integration test the plumbing. You can easily test with a real database using docker for example. Note that you'll still use DI in this case, but you'll have far fewer classes and therefore fewer dependencies as well.