Test Class not working (Case/Event)

I need Test Class to test the standard functionality :

When you change a record’s owner, some items that are related to the record are also transferred to the new owner.

In my case
Case owner changed to ‘Y’ => Event owner changed to ‘Y’
You can check the documentation here : https://help.salesforce.com/articleView?id=account_owner_transfer.htm&type=5

My issue is when i execute the test class, the owner of the event doesn’t change.
Below my TestClass :
(i’ll get the users from my org)

@isTest
private class EventTest {
    @isTest
    static void ownerEventChangedTest(){
        User[] user1 = [SELECT Id FROM User WHERE Username='YYYYY1' LIMIT 1];
        System.debug('***** user1 : ' + JSON.serializePretty(user1));

        System.runAs(user1[0]){
            User[] user2 = [SELECT Id FROM User WHERE Username='YYYYY2' LIMIT 1];
            System.debug('***** user2 : ' + JSON.serializePretty(user2));
            
            // Create Case
            Case[] cases = new Case[]{};
            for(Integer i=0; i<1; i++){
                cases.add(new Case());
            }
            insert cases;
            System.debug('***** cases before update : ' + JSON.serializePretty(cases));
            
            // Create Event
            Event[] events = new Event[]{};
            for(Integer i=0; i<1; i++){
                events.add(new Event(WhatId = cases[0].Id, 
                                     StartDateTime = Date.today().addDays(2), // Future Event
                                     DurationInMinutes = 60));
            }
            insert events;
            System.debug('***** events inserted : ' + JSON.serializePretty(events));
            
            // Update Event with a new Owner (user2)
            Case[] caseToUpdate = new Case[]{};
            for(Case c : [SELECT Id, OwnerId FROM Case WHERE Id IN : cases]){
                if(!user2.isEmpty()){
                    System.debug('***** inside for old Owner: ' + JSON.serializePretty(c.OwnerId));
                    System.debug('***** inside for new Owner : ' + JSON.serializePretty(user2[0].Id));
                    c.OwnerId = user2[0].Id;
                    caseToUpdate.add(c);
                }
            }
            
            // Update the case
            Test.startTest();
            update caseToUpdate;
            Test.stopTest();
            
            // Get the new Owner
            String newCaseOwner = [SELECT Id, OwnerId FROM Case LIMIT 1].OwnerId;
            System.debug('***** case after update : ' + JSON.serializePretty([SELECT Id, OwnerId FROM Case]));
            
            // Get Events
            Event[] events2 = [SELECT Id, Owner.Name, OwnerId, WhatId, StartDateTime, EndDateTime FROM Event];
            System.debug('***** event after update of the Case : ' + JSON.serializePretty(events2));
            
            // Check if new owner of Event is the owner of the Case 
            // ===> 
            // The owner of the Event IS NOT changed
            System.assertEquals(newCaseOwner, events2[0].OwnerId, 'Wrong Owner');
        }
    }
}

Any idea please?