def METHOD_NAME(self):
    mod = op.models.physics.ad_dif_conductance.ad_dif
    self.phase.add_model(propname='throat.ad_dif_conductance',
                         model=mod, s_scheme="upwind")
    actual = self.phase['throat.ad_dif_conductance'].mean()
    assert_allclose(actual, desired=19.583333)