idxSel.addChangedField(field1Id, null, null);
idxSel.addChangedField(field2Id, Bytes.toBytes("foo1"), Bytes.toBytes("foo2"));
idxSel.addChangedField(field3Id, Bytes.toBytes("foo3"), null);
idxSel.addChangedField(field4Id, null, Bytes.toBytes("foo4"));
json = event.toJsonBytes();
event = new RecordEvent(json, idGenerator);
List<RecordEvent.FieldChange> fieldChanges = event.getIndexRecordFilterData().getFieldChanges();
assertEquals(4, fieldChanges.size());