Test class for Transaction Finalizer is not working

Question

I am stuck in the test class for the Transaction Finalizer class. Every time when we create an exception for Queueable class then Finalizer class executing and then the test class throws the error on the test method and also not handled by try catch.

Below is my Queueable class Sample code:

public class QueueableClass implements Queueable {

    public void execute (QueueableContext context) {

    QueueableFinalizer finalizer = new QueueableFinalizer();
    System.attachFinalizer(finalizer);

   // Below code will failed Queueable because of System.LimitException: Too many DML 
   // statements: 151 And then Finalizer class will be Executes.

     if(Test.isRunningTest()){

     while (true) { // results in limit error
            Account a = new Account();
            a.Name = 'Account-Number-';
            insert a;
        }
         }
           }

Below is my Finalizer class Sample code:

   public class QueueableFinalizer implements Finalizer{

         public void execute(FinalizerContext ctx) { 
    
    // here we rerun the Queueable by using the system.Queueable
            
}
}

Below is my Test class Sample code for Finalizer:

   public static testMethod void testToFailQueueable() {

   test.startTest();
    try{
        System.enqueueJob(new QueueableClass ());  // here Too many DML Statement Error Occur.
        
    }catch(Exception e){
        
    }
    test.stopTest();
         
  
  }

Please suggest to me how to implement the test class for Finalizer. Thank you!

Answer 1

Since Async operations run in Sync manner inside test.startTest and test.stopTest().

You wont be able to capture LimitException with a try catch.

No need to test unhandled exceptions from test class. In documentation its mentioned that no matter what happens Finalizer will get called. So you can rest assure that it will get called.

Better throw a DML Exception when a test is running and test finalizer as LimitExceptions cannot be caught.

Test Class:

@IsTest
static void testLimitFinalizer() {
    try {
        Test.startTest();
        System.enqueueJob(new QueueableClassLimit());
        Test.stopTest();
    } catch (Exception e){
        System.debug(e);
    }
}

---

public class QueueableClassLimit implements Queueable {

    public void execute(QueueableContext context) {

        QueueableFinalizer finalizer = new QueueableFinalizer();
        System.attachFinalizer(finalizer);

        // Below code will failed Queueable because of System.LimitException: Too many DML
        // statements: 151 And then Finalizer class will be Executes.

        if (Test.isRunningTest()) {

            throw new DmlException('Test My Finalizer');
        }
    }
}

---

public class QueueableFinalizer implements Finalizer{

    public void execute(FinalizerContext ctx) {

        System.debug('Test Finalizer');

    }
}

Test class passes: