def test_electronegativity(self):
sm = StructureMatcher(ltol=0.2, stol=0.3, angle_tol=5)
s1 = read_structure(os.path.join(test_dir, "Na2Fe2PAsO4S4.cif"))
s2 = read_structure(os.path.join(test_dir, "Na2Fe2PNO4Se4.cif"))
self.assertAlmostEqual(sm.fit_with_electronegativity(s1, s2),
{Composition('S'): Composition('Se'), Composition('As'): Composition('N')})
