How to boot up a test pubsub emulator from python for automated testing
This is how I usually do:
1. I create a python client class which does publish and subscribe with the topic, project and subscription used in emulator.
Note: You need to set PUBSUB_EMULATOR_HOST=localhost:8085 as env in your python project.
2. I spin up a pubsub-emulator as a docker container.
Note: You need to set some envs, mount volumes and expose port 8085.
set following envs for container:

PUBSUB_EMULATOR_HOST
PUBSUB_PROJECT_ID
PUBSUB_TOPIC_ID
PUBSUB_SUBSCRIPTION_ID


Write whatever integration tests you want to. Use publisher or subscriber from client depending on your test requirements.
I'm working on a flask API, which one of the endpoint is to receive a message and publish it to PubSub. Currently, in order to test that endpoint, I will have to manually spin-up a PubSub emulator from the command line, and keep it running during the test. It working just fine, but it wouldn't be ideal for automated test. 
I wonder if anyone knows a way to spin-up a test PubSub emulator from python? Or if anyone has a better solution for testing such an API?