'Check size in derived pixel units.'

def test_size_pixel(self):

    size = ((0.3 * u.arcsec) / ((0.1 * u.arcsec) / u.pixel))
    c = Cutout2D(self.data, (2, 2), size)
    assert (c.data.shape == (3, 3))
    assert (c.data[(0, 0)] == 5)
    assert (c.slices_original == (slice(1, 4), slice(1, 4)))
    assert (c.slices_cutout == (slice(0, 3), slice(0, 3)))
