diff --git a/tests/test_slicefinder.py b/tests/test_slicefinder.py
index 1bbd901..0c185aa 100644
--- a/tests/test_slicefinder.py
+++ b/tests/test_slicefinder.py
@@ -9,6 +9,8 @@
 
 from sliceline import slicefinder
 
+np.random.seed(42)
+
 
 def test_dummify(benchmark, basic_test_data):
     """Test _dummify method."""