Function test_buffer_2

python/pathway/tests/test_column_properties.py:246–260

(append_only_1, append_only_2)

@pytest.mark.parametrize("append_only_1", [True, False])
@pytest.mark.parametrize("append_only_2", [True, False])
def test_buffer_2(append_only_1, append_only_2):
    class Schema(pw.Schema):
        a: int = pw.column_definition(append_only=append_only_1)
        b: int = pw.column_definition(append_only=append_only_2)

    table = table_from_datasource(TestDataSource(schema=Schema))
    result = table._buffer(pw.this.a + 10, pw.this.a)

    assert result._id_column.properties.append_only == append_only_1
    assert result.a._column.properties.append_only == append_only_1
    assert result.b._column.properties.append_only == (append_only_1 and append_only_2)
    # not obvious that it requires append_only_1 but if column `a` isn't append only and
    # column `b` is, we can have a situation when an old row leaves the buffer immediately
    # and a new row is kept. Then row is doesn't exist on the output for some time
    # so column `b` can't be append-only.


@pytest.mark.parametrize("append_only", [True, False])