Django Test Performance

Use this as the orchestration skill for speeding up a Django test suite. Do not start by changing settings blindly; first measure the suite and then pick the smallest safe optimization with a repeatable verification command.

Core Workflow

1. Establish a baseline.

   • Run the same command developers or CI use.
   • Capture wall-clock time, runner, settings module, database backend, worker count, and branch.
   • If the cause is unclear, use django-test-profiling before changing behavior.

2. Classify the dominant cost.

   • Startup/import/discovery: reduce collection scope and expensive app initialization.
   • Database creation/migrations: reuse DB locally, squash migration history, or improve database storage.
   • Per-test setup: reduce fixture data, use factories, and use setUpTestData.
   • External backends: replace file storage, cache, task queues, and instrumentation with test-safe backends.
   • Long tail of tests: parallelize after isolation checks.