diff --git a/tests/python/unittest/test_optimizer.py b/tests/python/unittest/test_optimizer.py
index 985220a30b2c..b6c902b13370 100644
--- a/tests/python/unittest/test_optimizer.py
+++ b/tests/python/unittest/test_optimizer.py
@@ -358,7 +358,7 @@ def test_adam():
               {'rescale_grad': 0.8, 'wd': 0.05}]
     for kwarg in kwargs:
         compare_optimizer(opt1(**kwarg), opt2(**kwarg), shape, np.float32)
-        compare_optimizer(opt1(**kwarg), opt2(**kwarg), shape, np.float32, w_stype='row_sparse')
+        compare_optimizer(opt1(**kwarg), opt2(**kwarg), shape, np.float32, g_stype='row_sparse')
 
 # RMSProp
 class PyRMSProp(mx.optimizer.Optimizer):