Method test_adapt_result_columns

test/sql/test_resultset.py:2882–2929

test adaptation of a CursorResultMetadata to another one. This copies the _keymap from one to the other in terms of the selected columns of a target selectable. This is used by the statement caching process to reuse the CursorResultMetadata from the cached statemen

(self, connection, stmt_fn)

        argnames="stmt_fn",
    )
    def test_adapt_result_columns(self, connection, stmt_fn):
        """test adaptation of a CursorResultMetadata to another one.


        This copies the _keymap from one to the other in terms of the
        selected columns of a target selectable.

        This is used by the statement caching process to reuse the
        CursorResultMetadata from the cached statement against the same
        statement sent separately.

        """

        stmt1 = stmt_fn(self)
        stmt2 = stmt_fn(self)

        eq_(stmt1._generate_cache_key(), stmt2._generate_cache_key())

        column_linkage = dict(
            zip(stmt1.selected_columns, stmt2.selected_columns)
        )

        for i in range(2):
            try:
                result = connection.execute(stmt1)

                mock_context = Mock(
                    compiled=result.context.compiled, invoked_statement=stmt2
                )
                existing_metadata = result._metadata
                adapted_metadata = existing_metadata._adapt_to_context(
                    mock_context
                )

                eq_(existing_metadata.keys, adapted_metadata.keys)

                for k in existing_metadata._keymap:
                    if isinstance(k, ColumnElement) and k in column_linkage:
                        other_k = column_linkage[k]
                    else:
                        other_k = k

                    is_(
                        existing_metadata._keymap[k],
                        adapted_metadata._keymap[other_k],
                    )
            finally:
                result.close()

    @testing.combinations(
        _adapt_result_columns_fixture_one,