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 db_version(engine, abs_path, init_version):
    """Show the current version of the repository.

    :param engine:  SQLAlchemy engine instance for a given database
    :param abs_path: Absolute path to migrate repository
    :param version:  Initial database version
    """
    repository = _find_migrate_repo(abs_path)
    try:
        return versioning_api.db_version(engine, repository)
    except versioning_exceptions.DatabaseNotControlledError:
        meta = sqlalchemy.MetaData()
        meta.reflect(bind=engine)
        tables = meta.tables
        if len(tables) == 0 or 'alembic_version' in tables:
            db_version_control(engine, abs_path, version=init_version)
            return versioning_api.db_version(engine, repository)
        else:
            raise exception.DbMigrationError(
                message=_(
                    "The database is not under version control, but has "
                    "tables. Please stamp the current version of the schema "
                    "manually."))