private void checkSimpleArrayAdd(DocumentUpdate update) {
        Set<String> toAdd = new HashSet<>();
        FieldUpdate x = update.getFieldUpdate("actualarray");
        for (ValueUpdate<?> v : x.getValueUpdates()) {
            AddValueUpdate adder = (AddValueUpdate) v;
            toAdd.add(((StringFieldValue) adder.getValue()).getString());
        }
        assertEquals(2, toAdd.size());
        assertTrue(toAdd.contains("person"));
        assertTrue(toAdd.contains("another person"));
    }
Basic test of JSON streams to Vespa document instances.

@author Steinar Knutsen
@author bratseth
document/src/test/java/com/yahoo/document/json/JsonReaderTestCase.java