Hcfyk

I moved a method that sets addError() from a trigger into a Helper class. As I started writing test code for it it seems like the addError() is not actually preventing DML operations for the records that get modified in the helper class.

The information from the SF SObject class page states:
Marks a trigger record with a custom error message and prevents any DML operation from occurring.

Does this mean that addError() will not work outside of a trigger class?

EDIT

Adding some sample code.

public class MyHelperClass() {

    public static void someMethod(Opportunity opp) {

        opp.My_Field__c.addError('Some error');

        insert opp;

    }

}

And sample test for it without any asserts:

@IsTest

private class MyHelperClass_Test() {

    @IsTest

    static void someTest() {

        Opportunity opp = new Opportunity();

        opp.Name = 'Some Name';

        opp.StageName = 'Prospect';

        opp.CloseDate = Date.today().addDays(30);



        MyHelperClass.someMethod(opp);

    }

}

The above inserts the opportunity and does not trigger an exception. Am I doing something wrong?

It only works on trigger context records, but it can be applied to those records outside of a trigger. You cannot call this method on a record which is not yet in a trigger context, then have the error carry through to the trigger context.

This code won't prevent DML:

Account record = new Account();

record.addError('You cannot insert this record');

insert record;

However, this code will:

trigger Account on Account (before insert)

{

    PreventDml.validate(trigger.new);

}

public with sharing class PreventDml

{

    public void validate(List<SObject> records)

    {

        for (SObject record : records)

        {

            record.addError('You cannot insert this record');

        }

    }

}

If you are trying to test this code, the only realistic, effective way to make sure it does what you want is to run the trigger. For example, in this scenario I might have a test like:

@IsTest

class AccountTriggerTests

{

    @IsTest static void testPreventDml()

    {

        DmlException expectedException;

        Test.startTest();

            try

            {

                insert new Account();

            }

            catch (DmlException dmx)

            {

                expectedException = dmx;

            }

        Test.stopTest();



        system.assertNotEquals(null, expectedException,

            'You should not be able to insert any Account');

        system.assertEquals(0, [SELECT count() FROM Account],

            'The database should be unchanged');

    }

}

addError won't block future DML operations, only those already in progress. You can use addError in any class, but it won't have any effect on future operations. As an example of what would work:

trigger myFieldBlock on Opportunity {

  myFieldBlock.validate(Trigger.new);

}

public class myFieldBlock {

  public static void validate(Opportunity records) {

    records[0].My_Field__c.addError('Some error');

  }

}

You can also use addError to display errors on a Visualforce page:

public class VFController {

  public Account record { get; set; }

  public VFController() {

    record = new Account();

  }

  public void showError() {

    record.Name.addError('Some error');

  }

}

<apex:page controller="VFController">

  <apex:form>

    <apex:inputField value="{!record.Name}" />

    <apex:commandButton value="Show Error" action="{!showError}" />

  </apex:form>

</apex:page>