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 _recreate_table(self, table, column=None, delta=None, omit_uniques=None):
    """Recreate the table properly

    Unlike the corresponding original method of sqlalchemy-migrate this one
    doesn't drop existing unique constraints when creating a new one.

    """

    table_name = self.preparer.format_table(table)

    # we remove all indexes so as not to have
    # problems during copy and re-create
    for index in table.indexes:
        index.drop()

    # reflect existing unique constraints
    for uc in self._get_unique_constraints(table):
        table.append_constraint(uc)
    # omit given unique constraints when creating a new table if required
    table.constraints = set([
        cons for cons in table.constraints
        if omit_uniques is None or cons.name not in omit_uniques
    ])

    self.append('ALTER TABLE %s RENAME TO migration_tmp' % table_name)
    self.execute()

    insertion_string = self._modify_table(table, column, delta)

    table.create(bind=self.connection)
    self.append(insertion_string % {'table_name': table_name})
    self.execute()
    self.append('DROP TABLE migration_tmp')
    self.execute()