diff --git a/extra_requirements/requirements-tests.txt b/extra_requirements/requirements-tests.txt
index 0d1538633..923550de2 100644
--- a/extra_requirements/requirements-tests.txt
+++ b/extra_requirements/requirements-tests.txt
@@ -1,3 +1,4 @@
 # File for the requirements of straxen with the automated tests
 git+https://github.com/AxFoundation/strax
 git+https://github.com/XENONnT/ax_env
+wfsim==0.6.1