System.UnexpectedException: Error processing messages in Test Class for Batch Apex

Question

Error Message

System.UnexpectedException: Error processing messages

Stack Trace

Class.System.Test.stopTest: line 24, column 1 Class.payout.BIgObj_Test.MyMethod: line 31, column 1

Batch Class

global class ArchiveALCTtoBigObj_Batch implements Database.Batchable<sObject>,Database.Stateful{

global final String paid;
global set <string> AdID = New set <string> ();
global ArchiveALCTtoBigObj_Batch(String pid){

    pa = pid;




}

global Database.QueryLocator start(Database.BatchableContext BC){
    DescribeSObjectResult describeResult = Account.getSObjectType().getDescribe();    
    List<String> fieldNames = new List<String>( describeResult.fields.getMap().keySet() );  
    String query =    ' SELECT ' +
        String.join( fieldNames, ',' ) +
        ' FROM ' +
        describeResult.getName()+
        ' WHERE ' +
        ' pa__c = :paid '; 
    System.debug('Al query = '+query);
    return Database.getQueryLocator(query);

}

global void execute(Database.BatchableContext BC, List<Account> scope){



    List <AccountBigObj__b> BObj_ALlist = new List<AccountBigObj__b>();


    for(Account AL : Scope ){

        AccountBigObj__b BObj_AL = new AccountBigObj__b();

        //Logic to assigning values from account to BigObject


        AdID.add(AL.ID);
        BObj_ALlist.add(BObj_AL);


    }

    If(BObj_ALlist.size()>0){
        database.insertImmediate(BObj_ALlist);

    }
}

global void finish(Database.BatchableContext BC){

    ArchiveCTtoBigObj_Batch ACT = new ArchiveCTtoBigObj_Batch(AdID);
    Database.executeBatch( ACT, 1 );
}

Batch Class 2

global class ArchiveCTtoBigObj_Batch implements database.Batchable<SObject>,Database.allowscallouts {

public set <string> ArchiveALCTtoBigObj_Batchid  = New set <string> ();

global ArchiveCTtoBigObj_Batch(set <String> ALId){

    this.ArchiveALCTtoBigObj_Batchid = ALId;

}

global database.QueryLocator Start(Database.BatchableContext bc) {


    DescribeSObjectResult describeResult = Contact.getSObjectType().getDescribe();    
    List<String> fieldNames = new List<String>( describeResult.fields.getMap().keySet() );  
    String query =    ' SELECT ' +
        String.join( fieldNames, ',' ) +
        ' FROM ' +
        describeResult.getName()+
        ' WHERE ' +
        ' AccountId = :ArchiveALCTtoBigObj_Batchid '; 

    return Database.getQueryLocator(query);



}
global void Execute(Database.BatchableContext bc, list<Contact>Scope){

    System.debug('Scope = '+Scope);
    List<ContactBigObject__b> BigObj_CTList = new List<ContactBigObject__b>();

    For(Contact CN : Scope){

       ContactBigObject__b BigObj_CT = new ContactBigObject__b();
        //Logic to assigning values from object to bigObject
        BigObj_CTList.add(BigObj_CT);


        }
             If(BigObj_CTList.size()>0){
              System.debug('List is not Empty');
            database.insertImmediate(BigObj_CTList);

    }


}

global void finish(Database.BatchableContext BC){
}

Test Class

@isTest
public class BIgObj_Test {
    public testmethod static void MyMethod(){

        Id ART = Schema.SObjectType.Account.getRecordTypeInfosByName().get('Ad').getRecordTypeId();



        Account A1 = new Account();
        A1.RecordTypeId = ART;
        A1.Name = 'Test Account';
        insert A1;

        Contact c1 = new Contact();
        c1.name = 'TestContact';
        c1.AccountId = A1.id;

        insert c1; 





        Test.startTest();

        ArchiveALCTtoBigObj_Batch ALBOBatch1 = New ArchiveALCTtoBigObj_Batch (A1.id);
        Database.executeBatch(ALBOBatch1,1);



        Test.stopTest();        



    }

Answer 1

I simply wrote a test class to insert a big object.

@IsTest
    static void testBehavior() {


        Test.startTest();
        Database.insertImmediate(new BigAccount__b(Account_Name__c= 'My Big Account'));
        Test.stopTest();
    }

Nothing fancy, plain simple, and when I run it I get the error.

Error 500/Server Error - UNKNOWN_EXCEPTION: An unexpected error occurred. Please include this ErrorId if you contact support: 833447077-35221 (1201933628)

I tried querying my Big Object table, and I could still see the test record being inserted in the actual database. This is one of the cases where test context does not respect execution context boundaries.

FROM SF docs:

Apex tests that use mixed DML calls are not allowed and fail. If you write only to the Big Object, the test inserts bad data into the target big object that you have to delete manually. To contain test DML calls to the target big object, use a mocking framework with the batch Apex stub API instead.

So apprently the testing framework is yet to be matured to test anything related to Big Objects. You have to use mocking frame from fflib or standard sf stub api.