If I only use a library during test suite runs, should it be in normal or dev packages in my Pipfile?

• We use built-in unittest (or Django's wrappers) for testing a Python project.
• In some of those tests, we use libs like freezegun or mock, which aren't used anywhere in the production codebase.
• Our CI that runs tests installs all deps before a test run, so usually we'd put those in dev-deps.

Is it common to leave those in the dev-packages section of the Pipfile, or should test-related packages also reside in packages?