'Test the copy function for variable types.'

def test_var_copy(self):

    x = Variable(3, 4, name='x')
    y = x.copy()
    self.assertEqual(y.size, (3, 4))
    self.assertEqual(y.name(), 'x')
    x = Semidef(5, name='x')
    y = x.copy()
    self.assertEqual(y.size, (5, 5))
