@Test
    public void testAssignMathTargetFieldNotSet() {
        Document doc = new Document(docMan.getDocumentType("foobar"), new DocumentId("id:ns:foobar::foooo"));
        DocumentUpdate docUp = new DocumentUpdate(docType, new DocumentId("id:ns:foobar::bar"));
        docUp.addFieldPathUpdate(new AssignFieldPathUpdate(doc.getDataType(), "num", "", "100"));
        docUp.applyTo(doc);
        assertEquals(new IntegerFieldValue(100), doc.getFieldValue(doc.getField("num")));
    }
Tests applying and serializing document updates.

@author Einar M R Rosenvinge
document/src/test/java/com/yahoo/document/DocumentPathUpdateTestCase.java