diff --git a/tests/unit/features/MockFeatures.h b/tests/unit/features/MockFeatures.h
index d739957809d..253728bef61 100644
--- a/tests/unit/features/MockFeatures.h
+++ b/tests/unit/features/MockFeatures.h
@@ -11,6 +11,14 @@ namespace shogun {
 			MOCK_CONST_METHOD0(get_num_vectors, int32_t());
 
 			virtual const char* get_name() const { return "MockCFeatures"; }
+
+		protected:
+			virtual CSGObject *create_empty() const
+			{
+				auto copy = new MockCFeatures();
+				SG_REF(copy)
+				return copy;
+			};
 	};
 
 }  // namespace shogun
diff --git a/tests/unit/labels/MockLabels.h b/tests/unit/labels/MockLabels.h
index 7354b0b644b..cb1a3a639c5 100644
--- a/tests/unit/labels/MockLabels.h
+++ b/tests/unit/labels/MockLabels.h
@@ -12,6 +12,14 @@ namespace shogun {
 			MOCK_METHOD0(get_values, SGVector<float64_t>());
 
 			virtual const char* get_name() const { return "MockCLabels"; }
+
+		protected:
+			virtual CSGObject *create_empty() const
+			{
+				auto copy = new MockCLabels();
+				SG_REF(copy)
+				return copy;
+			};
 	};
 
 }  // namespace shogun
diff --git a/tests/unit/multiclass/BaggingMachine_unittest.cc b/tests/unit/multiclass/BaggingMachine_unittest.cc
index 5ade2eab432..741d4669e19 100644
--- a/tests/unit/multiclass/BaggingMachine_unittest.cc
+++ b/tests/unit/multiclass/BaggingMachine_unittest.cc
@@ -93,7 +93,7 @@ TEST_F(BaggingMachine, mock_train)
 	bm->parallel->set_num_threads(1);
 	bm->put<CMachine>("machine", bm);
 	bm->put<int32_t>("bag_size", bag_size);
-	bm->put<int32_t>("num_bag", num_bags);
+	bm->put<int32_t>("num_bags", num_bags);
 	bm->put<CCombinationRule>("combination_rule", dynamic_cast<CCombinationRule*>(mv));
 
 	ON_CALL(mm, train_machine(_))