How to fix race conditions of tests that access the database

[medihack]

When using PostgreSQL as a test database, I get sporadic failing tests (mostly resetPassword.test.ts), because tests are run in parallel and then race conditions happen while resetting the database with db.$reset(). I am not sure if this also happens with SQLite. Maybe not because it is simply faster. But we should make sure that those race conditions won't happen. One option would be to run Jest with --runInBand option. This make the whole test suite slower, but it is the easiest way to fix this. There are a lot of other ways to solve this (mostly more complicated, but keeping parallel testing). One is to create a new database for every test and destroying it afterwards. Another one is to roll back the transaction somehow (I think Django does it that way). I am sure there are several others.

Resources:
https://github.com/Quramy/jest-prisma
https://jaketrent.com/post/isolate-jest-integration-test-shared-database/
https://stackoverflow.com/a/60819664/166229
https://blog.ludicroushq.com/a-better-way-to-run-integration-tests-with-prisma-and-postgresql
https://www.prisma.io/docs/guides/testing/integration-testing
prisma/prisma#2083 (comment)
https://selimb.hashnode.dev/speedy-prisma-pg-tests