def test_abcd_shunt_element(self):
        """
        Shunt elements of admittance Y:

        ○---------○
            |
           [Y]
            |
        ○---------○

        have ABCD matrix of the form:
        [ 1  0 ]
        [ Y  1 ]
        """
        R = 1.0  # Ohm
        ntw = self.dummy_media.shunt(self.dummy_media.resistor(R)**self.dummy_media.short())
        npy.testing.assert_array_almost_equal(ntw.a[:,0,0], 1.0)
        npy.testing.assert_array_almost_equal(ntw.a[:,0,1], 0.0)
        npy.testing.assert_array_almost_equal(ntw.a[:,1,0], 1.0/R)
        npy.testing.assert_array_almost_equal(ntw.a[:,1,1], 1.0)