def METHOD_NAME(expr, expected):
    grid = Grid((10, 10))
    x, y = grid.dimensions
    x0 = x + x.spacing/2  # noqa
    y0 = y + y.spacing/2  # noqa
    a = Function(name="a", grid=grid, staggered=NODE)  # noqa
    b = Function(name="b", grid=grid, staggered=x)  # noqa
    c = Function(name="c", grid=grid, staggered=y, parameter=True)  # noqa
    d = Function(name="d", grid=grid)  # noqa
    assert eval(expr) == eval(expected)