def test_view_of_view(matrix_type, subset_func, subset_func2):
    adata = gen_adata((30, 15), X_type=matrix_type)
    adata.raw = adata
    if subset_func is single_subset:
        pytest.xfail("Other subset generating functions have trouble with this")
    var_s1 = subset_func(adata.var_names, min_size=4)
    var_view1 = adata[:, var_s1]
    var_s2 = subset_func2(var_view1.var_names)
    var_view2 = var_view1[:, var_s2]
    assert var_view2._adata_ref is adata
    obs_s1 = subset_func(adata.obs_names, min_size=4)
    obs_view1 = adata[obs_s1, :]
    obs_s2 = subset_func2(obs_view1.obs_names)
    assert adata[obs_s1, :][:, var_s1][obs_s2, :]._adata_ref is adata

    view_of_actual_copy = adata[:, var_s1].copy()[obs_s1, :].copy()[:, var_s2].copy()

    view_of_view_copy = adata[:, var_s1][obs_s1, :][:, var_s2].copy()

    assert_equal(view_of_actual_copy, view_of_view_copy, exact=True)
def _contour(ax, title, elements, values, label='', isa=None):
    from matplotlib.patches import Polygon
    from matplotlib.collections import PatchCollection
    if ax == 0:
        ax = plt.gca()
    ax.set_aspect('equal')
    ax.set_title(title, fontsize=18)
    if isa:
        for se in isa.superelements:
            ax.add_patch(Polygon([n.xy
                                  for nc in se.nodechains
                                  for n in nc.nodes],
                                 color='gray', alpha=0.1, lw=0))
    valid_values = np.logical_not(np.isnan(values))
    patches = np.array([Polygon([v.xy for v in e.vertices])
                       for e in elements])[valid_values]
    # , cmap=matplotlib.cm.jet, alpha=0.4)
    p = PatchCollection(patches, alpha=1.0, match_original=False)
    p.set_array(np.asarray(values)[valid_values])
    ax.add_collection(p)
    cb = plt.colorbar(p)
    for patch in np.array([Polygon([v.xy for v in e.vertices],
                                   fc='white', alpha=1.0)
                           for e in elements])[np.isnan(values)]:
        ax.add_patch(patch)
    if label:
        cb.set_label(label=label, fontsize=18)
    ax.autoscale(enable=True)
    ax.axis('off')