diff --git a/tests/distributions/test_custom.py b/tests/distributions/test_custom.py
index 5b1de16178..5f2cef54f0 100644
--- a/tests/distributions/test_custom.py
+++ b/tests/distributions/test_custom.py
@@ -287,7 +287,7 @@ def test_multivariate_insufficient_signature(self):
         with pytest.raises(
             NotImplementedError, match="signature is not sufficient to infer the support shape"
         ):
-            CustomDist.dist(signature="(n)->(m)")
+            CustomDist.dist([0], signature="(n)->(m)")
 
 
 class TestCustomSymbolicDist: