@Test
    public void testPartialUpdateWithMultipleFieldsClear() {
        try {
            var tester = new PartialUpdateTester();

            DocumentUpdate input = new DocumentUpdate(tester.inputType, "id:ns:test::");
            input.addFieldUpdate(FieldUpdate.createClear(tester.inputType.getField("stringField")));

            DocumentUpdate output = tester.process(input);
            assertEquals(1, output.fieldUpdates().size());
            var fieldUpdate = output.fieldUpdates().iterator().next();
            assertEquals(1, fieldUpdate.getValueUpdates().size());
            var valueUpdate = fieldUpdate.getValueUpdates().iterator().next();
            assertTrue(valueUpdate instanceof AssignValueUpdate);
            assertEquals("", valueUpdate.getValue().getWrappedValue());
            fail("Expected exception");
        }
        catch (IllegalArgumentException e) {
            assertEquals("Could not execute update 'clear' to field 'stringField' of type string: " +
                         "No indexing statement taking only 'stringField' as input",
                         Exceptions.toMessageString(e));
        }
    }
Test sending clear of 1 field only, when needing 2
docprocs/src/test/java/com/yahoo/docprocs/indexing/IndexingProcessorTestCase.java