def test_view_retains_ndarray_subclass():
    adata = ad.AnnData(np.zeros((10, 10)))
    adata.obsm["foo"] = np.zeros((10, 5)).view(NDArraySubclass)

    view = adata[:5, :]

    assert isinstance(view.obsm["foo"], NDArraySubclass)
    assert view.obsm["foo"].shape == (5, 5)
def test_hyperfocal_distance():
    f, N, c = symbols('f, N, c')
    assert hyperfocal_distance(f=f, N=N, c=c) == f**2/(N*c)
    assert ae(hyperfocal_distance(f=0.5, N=8, c=0.0033), 9.47, 2)