function assert_own_property(object, property_name, description) {
        assert(object.hasOwnProperty(property_name),
               "assert_own_property", description,
               "expected property ${p} missing", {p:property_name});
    }
Assert that ``object`` has an own property with name ``property_name``.

@param {Object} object - Object that should have the given property.
@param {string} property_name - Expected property name.
@param {string} [description] - Description of the condition being tested.