How do you deal with cloud tasks in dev/test?

Great question.

I built my own super simple router abstraction. Message comes in, goes into my router, which sends it to the right handler.

I only test the handler itself, without any need for the higher level tasks. This also means that I'm only thinly tied to GCP Tasks and can migrate to another system by just changing the router.

What we did was mock it to make the http request blocking.

Alternatively you can use ngrok(or similar) and a test task queue that is calling your service running on localhost tunneled via ngrok.