APEX Test Class Failure CPQ inserting more than 1 quote lines

Question

I am currently on Summer 2020 CPQ. When creating test classes with more than one Quote line being inserted I am getting the below error? Any ideas as to why? looking through the debug logs the id appears to be from the opportunity. I wrote it both ways where creating a list and inserting individually.

 SBQQ__QuoteLine__c soQuoteLine0 = new SBQQ__QuoteLine__c
        (
         SBQQ__Quote__c = soQuote.Id,
         SBQQ__Product__c = ProductStandAlone.Id,
         Host__c = h.Id
        );
        
    Insert soQuoteLine0;

system.debug(logginglevel.debug, 'DEBUG: soQuoteLine    0           ' + soQuoteLine0.id);

        SBQQ__QuoteLine__c soQuoteLine1 = new SBQQ__QuoteLine__c
        (
           
         SBQQ__Quote__c = soQuote.Id,
         SBQQ__Product__c = ProductStandAlone.Id,
         Host__c = h.Id
        );
     
  //   try{
         
         Insert soQuoteLine1;



List<SBQQ__QuoteLine__c> lines = new List<SBQQ__QuoteLine__c>();
    lines.add(new SBQQ__QuoteLine__c(SBQQ__Quote__c = q.Id, Host__c = h.Id, SBQQ__Product__c = p.Id));
    lines.add(new SBQQ__QuoteLine__c(SBQQ__Quote__c = q.Id, Host__c = h.Id, SBQQ__Product__c = p2.Id));
    Insert lines;


System.DmlException: Insert failed. First exception on row 0; first error: 
CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, SBQQ.QuoteLineAfter: execution of AfterInsert

caused by: System.ListException: Duplicate id in list: 0064C00000CZdzUQAT 

Class.SBQQ.QuoteOpportunitySynchronizer.upsertAndDelOpportunityLineItems: line 243, column 1
Class.SBQQ.QuoteOpportunitySynchronizer.updateOpportunityProducts: line 35, column 1
Class.SBQQ.QuoteService.calculateAndSynch: line 214, column 1
Class.SBQQ.QuoteService.processLineTriggerAfter: line 1380, column 1
Trigger.SBQQ.QuoteLineAfter: line 23, column 1: []

Answer 1

I had the same issue with my test class. Solved it by adding the pricebook Id to the opportunity and quote. The line items I now create via the pricebookentry, not via the product.

Hope this helps someone in the future coming across this issue.

Answer 2

The error seems to because you the product you are assigning to soQuoteLine1 is same as product for soQuoteLine0 and both are on the same quote.