Django more-than-unit tests, less than end-to-end tests

I'm working on a Django-based system that handles a lot of data. Data is imported from relatively large files (~ 1GB) into a database and the file system. After being imported, there are a lot of things that can be done with the data, including serving parts of it to an angular-based Frontend.

In order to test most of the backend functionality we need to populate the database and file system with data. The most straight-forward way we can think of to accomplish data is to run the import process as part of the tests.

When performing unit tests, the database is cleared before every test is run. This will force us to perform the import as the setUp of the test. The import is a lengthy process, and we'd much rather not repeat it for every test.

We need a way to somehow set up the system's state once and then use this state throughout the tests (sometimes rolling changes back, sometimes keeping them).

Is there a Django friendly test framework that will let me do that?