diff --git a/tests/unit_tests/test_stack_examples.py b/tests/unit_tests/test_stack_examples.py
index 81fda2d2..27b5123c 100644
--- a/tests/unit_tests/test_stack_examples.py
+++ b/tests/unit_tests/test_stack_examples.py
@@ -18,6 +18,7 @@ from openflexure_microscope_server.things.autofocus import AutofocusThing
 THIS_DIR = os.path.dirname(__file__)
 DATA_PATH = os.path.join(THIS_DIR, "data", "sharpness_test_cases.json")
 
+
 class MockCapture:
     """Simple mock object representing a captured image.