def METHOD_NAME(dg_trial_test):
    u, v = dg_trial_test
    cell = assemble(inner(u, v) * dx).M.values
    # each diagonal entry should be volume of cell
    assert np.allclose(np.diag(cell), 0.5)
    # all off-diagonals should be zero
    cell[range(2), range(2)] = 0.0
    assert np.allclose(cell, 0.0)