Nox sessions failing with no pip found #442
Description
System tests mysteriously failed on #438 and #440. The same four sessions failed with message that they were unable to find pip in the virtualenv created by nox.
Session default_cloud_sdk_authorized_user_configured_project-3.7 raised exception FileNotFoundError(2, "No such file or directory: '/tmpfs/src/github/google-auth-library-python/system_tests/.nox/default_cloud_sdk_authorized_user_configured_project-3-7/bin/pip'")
============================== 4 passed in 1.02s ===============================
Session grpc-3.7 was successful.
Ran multiple sessions:
* service_account-2.7: success
* service_account-3.7: success
* oauth2_credentials-2.7: success
* oauth2_credentials-3.7: success
* default_explicit_service_account-2.7: success
* default_explicit_service_account-3.7: success
* default_explicit_authorized_user-2.7: success
* default_explicit_authorized_user-3.7: success
* default_explicit_authorized_user_explicit_project-2.7: failed
* default_explicit_authorized_user_explicit_project-3.7: failed
* default_cloud_sdk_service_account-2.7: success
* default_cloud_sdk_service_account-3.7: success
* default_cloud_sdk_authorized_user-2.7: success
* default_cloud_sdk_authorized_user-3.7: success
* default_cloud_sdk_authorized_user_configured_project-2.7: failed
* default_cloud_sdk_authorized_user_configured_project-3.7: failed
* compute_engine-2.7: success
* compute_engine-3.7: success
* app_engine-2.7: success
* grpc-2.7: success
* grpc-3.7: success
The only things the failing sessions seem to have in common is that they have very long session names. Otherwise the setup is similar to the other sessions (configure_cloud_sdk, python versions).
This may have the same root cause as Autosynth PR failures.
More reading in case this happens again:
https://stackoverflow.com/questions/7911003/cant-install-via-pip-with-virtualenv