private static GlobalId createGlobalId(int docId) {
        return new GlobalId(
                new DocumentId(String.format("id:test:type::%d", docId)).getGlobalId());
    }
Tests serialization compatibility across Java and C++. The comparison is performed by comparing serialized Java
object graphs with the content of specific binary files. C++ unit tests serializes
identical data structures into these files.
Note: This test relies heavily on proper implementation of {@link Object#equals(Object)}!
searchlib/src/test/java/com/yahoo/searchlib/aggregation/GroupingSerializationTest.java