@Test
    public void testExceptionIfNoDataDestinationSet() {
        MockComponentsBuilder builder = new MockComponentsBuilder();
        builder.receiver.setConnectionSpec(null);
        builder.params = createVisitorParameters("id.user==1234");
        builder.params.setLocalDataHandler(null);
        builder.params.setRemoteDataHandler(null);
        try {
            builder.createMockComponents();
            fail("No exception thrown on missing data destination");
        } catch (IllegalStateException e) {
            assertEquals("No data destination specified", e.getMessage());
        }
    }
Test assembly of message traces in session. Trace level propagation
is already tested elsewhere.
documentapi/src/test/java/com/yahoo/documentapi/messagebus/MessageBusVisitorSessionTestCase.java