# Using the Test Mode Configuration

Airflow has a fixed set of “test mode” configuration options. You can load these at any time by calling `airflow.configuration.load_test_config()` (note this operation is not reversible!). However, some options (like the DAG_FOLDER) are loaded before you have a chance to call load_test_config(). In order to eagerly load the test configuration, set test_mode in airflow.cfg:

    [tests]
    unit_test_mode = True

Due to Airflow’s automatic environment variable expansion (see Setting Configuration Options), you can also set the env var `AIRFLOW__CORE__UNIT_TEST_MODE` to temporarily overwrite airflow.cfg.