In what environment is PostgreSQL usually run during unit testing to verify database functionality?

In Java unit testing for working with PostgreSQL, the following approaches are often used:

• Embedded PostgreSQL — a local instance of PostgreSQL is run in memory or on the local machine specifically for tests.

• Docker container with PostgreSQL — tests are run with a deployed database container, providing an isolated and reproducible environment.

• Test databases on CI server — a separate server with PostgreSQL accessible for tests.

• Using in-memory databases (e.g., H2) in PostgreSQL compatibility mode — for simplicity, but not always fully correct.