diff --git a/test/test_reduction.py b/test/test_reduction.py
index 5887df7a628c46fbf09539fdd48c08aaacd8e409..86e72c0c6644b7b9837a6d74da756c58344b1d6f 100644
--- a/test/test_reduction.py
+++ b/test/test_reduction.py
@@ -181,7 +181,7 @@ def test_recursive_nested_dependent_reduction(ctx_factory):
     # FIXME: Actually test functionality.
 
 
-@pytest.mark.parametrize("size", [128, 5, 113, 67])
+@pytest.mark.parametrize("size", [128, 5, 113, 67, 1])
 def test_local_parallel_reduction(ctx_factory, size):
     ctx = ctx_factory()