I'm getting this deprecation warning when running pytests on my app that uses Google Storage.

Environment details

Arch Linux
Python 3.7.1
google-api-core==1.5.1
google-auth==1.5.1
google-cloud-core==0.28.1
google-cloud-storage==1.13.0
google-resumable-media==0.3.1
googleapis-common-protos==1.5.5
pytest==3.9.1

Steps to reproduce

1. Create file test.py.
2. Add line from google.protobuf.pyext import _message to it.
3. Run pytest test.py (to install pytest first pip install pytest==3.9.1)
4. Pytest will print the following: test.py:1: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working from google.protobuf.pyext import _message

In my tests this warning comes from: google/protobuf/internal/api_implementation.py:154

Couldn't reproduce in shell, but pytest somehow catches this while running tests.