Correct. What I plan to do is use the stubs for actual development/unit testing with a faster iteration loop but then add a higher level end-to-end test that runs against real ECS. It'll docker-compose up a daemon and a user code repository onto ECS (which will scaffold all the ECS resources with tags), run a pipeline, and check that it worked. We can also run a longer-running pipeline and test termination. And then it'll docker-compose down.

I don't want to start with this approach though for a few reasons (that all more or less get summed up as "garbage collection"):

• if docker-compose up stands up an ECS task that can't actually run (like invalid config or something), we get stuck in an infinite loop where the CloudFormation stack never finishes applying. So we can never use docker compose down to tear it down (I believe the solution for this is to enable deployment circuit breaking https://aws.amazon.com/blogs/containers/announcing-amazon-ecs-deployment-circuit-breaker/)
• docker-compose up adds tags to all the resources it creates so I want to write a cleanup method that finds everything with those tags and destroys them (in case docker-compose down fails or is just incomplete)