diff --git a/tests/core/data/conftest.py b/tests/core/data/conftest.py
index 90cbc91..d9853cd 100644
--- a/tests/core/data/conftest.py
+++ b/tests/core/data/conftest.py
@@ -9,7 +9,7 @@
 def random_numpy_dense(shape):
     """Generate a random numpy dense matrix with the given shape."""
     out = np.random.random(shape) + 1j * np.random.random(shape)
-    return np.asarray(out)
+    return np.asarray(out) # This ensure the output is an ndarray.
 
 
 def random_node(shape):