Testing DMLException in future method

Question

Any ideas how I can test this one - only the DMLException and Exception parts

@future
public static void updateUserFlags(Set<Id> userIds ) {

    Logger.log(ShGl_Constants.INFO, 'ShMa_AveretekOptInUser.updateUserFlags', 'Start user update', null);
    // Create empty map for user updates
    Map<Id, User> userUpdateMap = new Map<Id, User>();

    // Iterate users for ids passed into future method
    for (User u2 : [SELECT Id, ShMa_OptInAveretek__c,
                    Is_Integrated__c, Contact.ShMa_OptInAveretek__c FROM User WHERE Id in: userIds]) {

        // Set user fields
        User u3 = new User( Id = u2.Id, Is_Integrated__c = false,
                            ShMa_OptInAveretek__c = u2.Contact.ShMa_OptInAveretek__c);
        userUpdateMap.put(u2.Id, u3); // add intsance of user to map
    }


    try {
        if (userUpdateMap.size() > 0) {
            update userUpdateMap.values(); // update user records in map
            Logger.log(ShGl_Constants.INFO, 'ShMa_AveretekOptInUser.updateUserFlags', 'End user update', null);
        }
    }

    // Start exception handing
    catch (DmlException e) {
        for (Integer i = 0; i < e.getNumDml(); i++) {
            Logger.log(ShGl_Constants.ERROR, 'ShMa_AveretekOptInUser.updateUserFlags', e.getDmlMessage(i), e.getDmlId(i));
        }
    } catch (Exception e) {
        Logger.log(ShGl_Constants.FATAL, 'ShMa_AveretekOptInUser.updateUserFlags', e.getMessage(), null);
    }

}

Answer 1

Move it to a separate method that takes in the list you want to update.

static void updateUsers(List<User> usersToUpdate)
{
    try
    {
        update usersToUpdate;
    }
    catch (DmlException dmx)
    {
        //do stuff
    }
}

And your test class:

@TestVisible
static testMethod void testUpdateUsers_Error()
{
    // no Id causes DmlException on update
    List<User> errorUsers = new List<User> { new User(); }

    DmlException unexpectedException;
    Test.startTest();
        try
        {
            updateUsers(errorUsers);
        }
        catch (DmlException dmx)
        {
            unexpectedException = dmx;
        }
    Test.stopTest();

    system.assertEquals(null, unexpectedException, 'Add a message');
    //additional assertions...
}