@Override
        public Progress process(Processing processing) {
            for (DocumentOperation op : processing.getDocumentOperations()) {
                assertEquals("called", processing.getVariable("processor2"));
                if (processing.getVariable("processor3") == null) {
                    processing.setVariable("processor3", "called");
                    return Progress.LATER;
                }
                ((DocumentPut)op).getDocument().setFieldValue("test", new StringFieldValue("done"));
            }
            return Progress.DONE;
        }
Asserts that a document processing service works
docproc/src/test/java/com/yahoo/docproc/DocumentProcessingAbstractTestCase.java