fix unit test

Author: zubaira

dhis-2/dhis-services/dhis-service-tracker/src/main/java/org/hisp/dhis/tracker/programrule/DefaultTrackerProgramRuleService.java

@@ -226,7 +226,7 @@ private Set<ProgramStageInstance> getEventsFromEnrollment(
             .filter(event -> event.getEnrollment().equals(enrollmentUid))
             .collect(
                 Collectors.toMap(
-                    Event::getUid,
+                    Event::getEvent,
                     event ->
                         eventTrackerConverterService.fromForRuleEngine(
                             bundle.getPreheat(), event)));

dhis-2/dhis-services/dhis-service-tracker/src/test/java/org/hisp/dhis/tracker/programrule/DefaultTrackerProgramRuleServiceTest.java

@@ -121,6 +121,9 @@ void shouldInvokeSpecificMethodWhenCalculatingRuleEffectsForTrackerEvents() {
     when(trackerBundle.getPreheat()).thenReturn(preheat);
     when(eventTrackerConverterService.fromForRuleEngine(any(TrackerPreheat.class), anyList()))
         .thenReturn(programStageInstances);
+    when(eventTrackerConverterService.fromForRuleEngine(
+            any(TrackerPreheat.class), any(Event.class)))
+        .thenReturn(programStageInstances.get(0));
     when(programRuleEngine.evaluateEnrollmentAndEvents(
             any(ProgramInstance.class), anySet(), anyList()))
         .thenReturn(Collections.emptyList());