For development, you'll use some good practices in PostgreSQL like a custom app schema and app user, with reduced explicitly granted privileges.
For test environment, you'll keep it simpler.
Use the postgres superuser and the public schema. The test configuration is also used for Circle CI.
From the Rideshare directory, run:
sh db/setup_test_database.sh, which sets uprideshare_testbin/rails test
Refer to .circleci/config.yml for the Circle CI config.
You should now have a test database, and tests should have passed.