diff --git a/tests/python/test_models.py b/tests/python/test_models.py
index 8c06d9de9..2308b1229 100644
--- a/tests/python/test_models.py
+++ b/tests/python/test_models.py
@@ -36,4 +36,13 @@ def test_custom_objective():
 	err = sum(1 for i in range(len(preds)) if int(preds[i]>0.5)!=labels[i]) / float(len(preds))
 	assert err < 0.1
 
-
+def test_fpreproc():
+	param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic'}
+	num_round = 2
+	def fpreproc(dtrain, dtest, param):
+		label = dtrain.get_label()
+		ratio = float(np.sum(label == 0)) / np.sum(label==1)
+		param['scale_pos_weight'] = ratio
+		return (dtrain, dtest, param)
+	xgb.cv(param, dtrain, num_round, nfold=5,
+       metrics={'auc'}, seed = 0, fpreproc = fpreproc)