diff --git a/interfaces/cython/cantera/test/test_kinetics.py b/interfaces/cython/cantera/test/test_kinetics.py
index 6abf4415a..158e69987 100644
--- a/interfaces/cython/cantera/test/test_kinetics.py
+++ b/interfaces/cython/cantera/test/test_kinetics.py
@@ -287,7 +287,7 @@ class TestReactionPath(utilities.CanteraTest):
                     # nodes
                     nodes2.add(A.strip())
                     spec = re.search('label="(.*?)"', B).group(1)
-                    self.assertTrue(spec not in species)
+                    self.assertNotIn(spec, species)
                     species.add(spec)
 
             # Make sure that the output was actually parsable and that we
diff --git a/interfaces/cython/cantera/test/test_thermo.py b/interfaces/cython/cantera/test/test_thermo.py
index 1ab3b49b3..7a911c009 100644
--- a/interfaces/cython/cantera/test/test_thermo.py
+++ b/interfaces/cython/cantera/test/test_thermo.py
@@ -136,7 +136,7 @@ class TestThermoPhase(utilities.CanteraTest):
 
         self.phase.name = 'something'
         self.assertEqual(self.phase.name, 'something')
-        self.assertTrue('something' in self.phase.report())
+        self.assertIn('something', self.phase.report())
 
     def test_ID(self):
         self.assertEqual(self.phase.ID, 'ohmech')