diff --git a/tests/unit/multiclass/BaggingMachine_unittest.cc b/tests/unit/multiclass/BaggingMachine_unittest.cc
index 9a02c478959..87fb4a10344 100644
--- a/tests/unit/multiclass/BaggingMachine_unittest.cc
+++ b/tests/unit/multiclass/BaggingMachine_unittest.cc
@@ -50,6 +50,7 @@ TEST(BaggingMachine, mock_train)
 	NiceMock<MockCMachine> mm; mm.ref();
 	CMajorityVote* mv = new CMajorityVote();
 
+	bm->parallel->set_num_threads(1);
 	bm->set_machine(&mm);
 	bm->set_bag_size(bag_size);
 	bm->set_num_bags(num_bags);
@@ -188,6 +189,7 @@ TEST(BaggingMachine,classify_CART)
 	CMajorityVote* cv=new CMajorityVote();
 	cart->set_feature_types(ft);
 	CBaggingMachine* c=new CBaggingMachine(feats,labels);
+	c->parallel->set_num_threads(1);
 	c->set_machine(cart);
 	c->set_bag_size(14);
 	c->set_num_bags(10);
diff --git a/tests/unit/multiclass/tree/RandomForest_unittest.cc b/tests/unit/multiclass/tree/RandomForest_unittest.cc
index 61fa729c3cd..b99753f609c 100644
--- a/tests/unit/multiclass/tree/RandomForest_unittest.cc
+++ b/tests/unit/multiclass/tree/RandomForest_unittest.cc
@@ -163,6 +163,7 @@ TEST(RandomForest,classify_nominal_test)
 	c->set_feature_types(ft);
 	CMajorityVote* mv = new CMajorityVote();
 	c->set_combination_rule(mv);
+	c->parallel->set_num_threads(1);
 	c->train(feats);
 
 	SGMatrix<float64_t> test(4,5);
@@ -232,6 +233,7 @@ TEST(RandomForest,classify_non_nominal_test)
 	c->set_feature_types(ft);
 	CMajorityVote* mv = new CMajorityVote();
 	c->set_combination_rule(mv);
+	c->parallel->set_num_threads(1);	
 	c->train(feats);
 
 	SGMatrix<float64_t> test(4,5);