I was seeing unexpected success on a test suite, it turns out I did not have the JDK installed correctly on my new machine.

When failures such as this occur firebase emulators:exec "exit 1" returns a success code and only i emulators: Shutting down emulators.

I didn't see I what the issue was until I used --debug. This could be a footgun for those using the emulators for integration tests. Having seen this I expect there may be similar classes of errors.