Travis stuck after starting firestore emulator in python

I have python library and I write some test for firestore. Install firestore through travis it installed successfully and start but after starting firestore rest of the travis config not work I wait for 5-6 minutes but nothing show in log then I cancel the build.
Here you can check the Build Log

before_install:
 - npm i -g firebase firebase-tools
 - firebase setup:emulators:firestore

install:
- pip install tox

before_script:
- firebase emulators:start --only firestore

script:
 - tox -v -e py

I also tried to start firestore in before_install

 before_install:
    - npm i -g firebase firebase-tools
    - firebase setup:emulators:firestore
    - firebase emulators:start --only firestore

This one is also not working. same problem check Build Log

Judging by https://github.com/firebase/quickstart-nodejs/tree/master/firestore-emulator/javascript-quickstart, firebase emulators:start does not return (note how that guide tells you to run tests in a different terminal window). So you need to run that command in background to be able to run anything else while it’s running (and kill the background process after you finish). See https://mywiki.wooledge.org/ProcessManagement on the Bash side of things.

You will also probably need to somehow wait until the emulator is running before starting your next command (parsing the output is one way but maybe it provides some other, more script-friendly indicator).

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