def test_double_index(subset_func, subset_func2):
    adata = gen_adata((10, 10))
    obs_subset = subset_func(adata.obs_names)
    var_subset = subset_func2(adata.var_names)
    v1 = adata[obs_subset, var_subset]
    v2 = adata[obs_subset, :][:, var_subset]

    assert np.all(asarray(v1.X) == asarray(v2.X))
    assert np.all(v1.obs == v2.obs)
    assert np.all(v1.var == v2.var)
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)