diff --git a/conftest.py b/conftest.py
index 6c17a79a683ac93fa0afa4f30a1a75d86a66b379..05007fb8aa4ce936dc0cbbfb34345f631098a5fe 100644
--- a/conftest.py
+++ b/conftest.py
@@ -14,6 +14,7 @@ try:
     pyximport.install(language_level=3)
 except ImportError:
     pass
+from lbmpy.phasefield.simplex_projection import simplex_projection_2d  # NOQA
 
 
 SCRIPT_FOLDER = os.path.dirname(os.path.realpath(__file__))