diff --git a/interfaces/cython/cantera/test/test_onedim.py b/interfaces/cython/cantera/test/test_onedim.py
index 172ee1ed5..fbce5b7ab 100644
--- a/interfaces/cython/cantera/test/test_onedim.py
+++ b/interfaces/cython/cantera/test/test_onedim.py
@@ -496,6 +496,14 @@ class TestDiffusionFlame(utilities.CanteraTest):
         with self.assertRaises(KeyError): # missing 'stoich'
             self.sim.strain_rate('stoichiometric', fuel='H2', oxidizer='H2O2')
 
+    def test_mixture_fraction(self):
+        self.create_sim(p=ct.one_atm)
+        Z = self.sim.mixture_fraction('H')
+        self.assertNear(Z[0], 1.0)
+        self.assertNear(Z[-1], 0.0)
+        self.assertTrue(all(Z >= 0))
+        self.assertTrue(all(Z <= 1.0))
+
 
 class TestCounterflowPremixedFlame(utilities.CanteraTest):
     referenceFile = '../data/CounterflowPremixedFlame-h2-mix.csv'
diff --git a/interfaces/cython/cantera/test/test_thermo.py b/interfaces/cython/cantera/test/test_thermo.py
index cf46bc1ea..578cce70c 100644
--- a/interfaces/cython/cantera/test/test_thermo.py
+++ b/interfaces/cython/cantera/test/test_thermo.py
@@ -40,6 +40,40 @@ class TestThermoPhase(utilities.CanteraTest):
         with self.assertRaises(ValueError):
             self.phase.n_atoms('H', 'CH4')
 
+    def test_elemental_mass_fraction(self):
+        self.phase.Y = 'H2O:0.5, O2:0.5'
+        Zo = self.phase.elemental_mass_fraction('O')
+        Zh = self.phase.elemental_mass_fraction('H')
+        Zar = self.phase.elemental_mass_fraction('Ar')
+
+        mO = self.phase.element_index('O')
+        self.assertEqual(Zo, self.phase.elemental_mass_fraction(mO))
+        self.assertNear(Zo, 0.5 + 0.5 * (15.9994 / 18.01528))
+        self.assertNear(Zh, 0.5 * (2.01588 / 18.01528))
+        self.assertEqual(Zar, 0.0)
+
+        with self.assertRaises(ValueError):
+            self.phase.elemental_mass_fraction('C')
+        with self.assertRaises(ValueError):
+            self.phase.elemental_mass_fraction(5)
+
+    def test_elemental_mole_fraction(self):
+        self.phase.X = 'H2O:0.5, O2:0.5'
+        Zo = self.phase.elemental_mole_fraction('O')
+        Zh = self.phase.elemental_mole_fraction('H')
+        Zar = self.phase.elemental_mole_fraction('Ar')
+
+        mO = self.phase.element_index('O')
+        self.assertEqual(Zo, self.phase.elemental_mole_fraction(mO))
+        self.assertNear(Zo, 0.5/3 + 0.5)
+        self.assertNear(Zh, 0.5*2/3)
+        self.assertEqual(Zar, 0.0)
+
+        with self.assertRaises(ValueError):
+            self.phase.elemental_mole_fraction('C')
+        with self.assertRaises(ValueError):
+            self.phase.elemental_mole_fraction(5)
+
     def test_weights(self):
         atomic_weights = self.phase.atomic_weights
         molecular_weights = self.phase.molecular_weights