EncounterService es = Context.getEncounterService();
        Encounter enc = es.getEncounter(3);
        enc.setEncounterDatetime(DateUtil.getDateTime(2008, 8, 1, 11, 0, 0, 0));
        es.saveEncounter(enc);

        EncounterCohortDefinition cd = new EncounterCohortDefinition();
        cd.setOnOrBefore(DateUtil.getDateTime(2008, 8, 1, 10, 0, 0, 0));
        Cohort c = Context.getService(CohortDefinitionService.class).evaluate(cd, null);
        Assert.assertTrue(c.contains(7));