def METHOD_NAME(expression_string, expected_message):
    document: Document = document_fixture()
    license_expression: LicenseExpression = spdx_licensing.parse(expression_string)
    parent_id = "SPDXRef-File"
    context = ValidationContext(
        parent_id=parent_id, element_type=SpdxElementType.LICENSE_EXPRESSION, full_element=license_expression
    )
    validation_messages: List[ValidationMessage] = validate_license_expression(license_expression, document, parent_id)
    expected_messages = [ValidationMessage(expected_message, context)]
    assert validation_messages == expected_messages