In testing a lot of IDL generated classes, a common pattern is the following:

    BSONObjBuilder builder;
    obj.serialize(&builder)
    auto doc = builder.obj();

In order to reduce the amount of copy/pasted code, the following method will be added to IDL generated classes for testing IDL classes.

BSONObj toBSON() {
    BSONObjBuilder builder;
    obj.serialize(&builder)
    return builder.obj();
}