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 _plot_surface(ax, x, y, z, labels, azim=None):
    """helper function for surface plots"""
    # ax.tick_params(axis='both', which='major', pad=-3)
    assert np.size(x) > 1 and np.size(y) > 1 and np.size(z) > 1
    if azim is not None:
        ax.azim = azim
    X, Y = np.meshgrid(x, y)
    Z = np.ma.masked_invalid(z)
    ax.plot_surface(X, Y, Z,
                    rstride=1, cstride=1,
                    cmap=cm.viridis, alpha=0.85,
                    vmin=np.nanmin(z), vmax=np.nanmax(z),
                    linewidth=0, antialiased=True)