def test_empty_coupling_class(self):
coupling = CouplingMap()
self.assertEqual(0, coupling.size())
self.assertEqual([], coupling.physical_qubits)
self.assertEqual([], coupling.get_edges())
self.assertFalse(coupling.is_connected())
self.assertEqual("", str(coupling))
def test_coupling_distance(self):
coupling_list = [(0, 1), (0, 2), (1, 2)]
coupling = CouplingMap(coupling_list)
self.assertTrue(coupling.is_connected())
physical_qubits = coupling.physical_qubits
result = coupling.distance(physical_qubits[0], physical_qubits[1])
self.assertEqual(1, result)
