diff --git a/GPy/testing/parameterized_tests.py b/GPy/testing/parameterized_tests.py
index 1ab0fd32..f3e0863f 100644
--- a/GPy/testing/parameterized_tests.py
+++ b/GPy/testing/parameterized_tests.py
@@ -121,15 +121,15 @@ class ParameterizedTest(unittest.TestCase):
     def test_default_constraints(self):
         self.assertIs(self.rbf.variance.constraints._param_index_ops, self.rbf.constraints._param_index_ops)
         self.assertIs(self.test1.constraints, self.rbf.constraints._param_index_ops)
-        self.assertListEqual(self.rbf.constraints.indices()[0].tolist(), range(2))
+        self.assertListEqual(self.rbf.constraints.indices()[0].tolist(), list(range(2)))
         from GPy.core.parameterization.transformations import Logexp
         kern = self.test1.kern
         self.test1.unlink_parameter(kern)
-        self.assertListEqual(kern.constraints[Logexp()].tolist(), range(3))
+        self.assertListEqual(kern.constraints[Logexp()].tolist(), list(range(3)))
 
     def test_constraints(self):
         self.rbf.constrain(GPy.transformations.Square(), False)
-        self.assertListEqual(self.test1.constraints[GPy.transformations.Square()].tolist(), range(self.param.size, self.param.size+self.rbf.size))
+        self.assertListEqual(self.test1.constraints[GPy.transformations.Square()].tolist(), list(range(self.param.size, self.param.size+self.rbf.size)))
         self.assertListEqual(self.test1.constraints[GPy.transformations.Logexp()].tolist(), [self.param.size+self.rbf.size])
 
         self.test1.kern.unlink_parameter(self.rbf)
@@ -182,8 +182,8 @@ class ParameterizedTest(unittest.TestCase):
 
     def test_add_parameter_in_hierarchy(self):
         self.test1.kern.rbf.link_parameter(Param("NEW", np.random.rand(2), NegativeLogexp()), 1)
-        self.assertListEqual(self.test1.constraints[NegativeLogexp()].tolist(), range(self.param.size+1, self.param.size+1 + 2))
-        self.assertListEqual(self.test1.constraints[GPy.transformations.Logistic(0,1)].tolist(), range(self.param.size))
+        self.assertListEqual(self.test1.constraints[NegativeLogexp()].tolist(), list(range(self.param.size+1, self.param.size+1 + 2)))
+        self.assertListEqual(self.test1.constraints[GPy.transformations.Logistic(0,1)].tolist(), list(range(self.param.size)))
         self.assertListEqual(self.test1.constraints[GPy.transformations.Logexp(0,1)].tolist(), np.r_[50, 53:55].tolist())
 
     def test_regular_expression_misc(self):