I get this error related to a Validation rule when I try to run a test on my Apex class (below) The fields related to the rule are bold. What am I doing wrong? If approval fields (Account and Merchant Application) are 'Approved' when Opportunity stage is 'Signed' why would I get the error from my validation when it meets criteria to not be an error?

Error Message	System.DmlException: Insert failed. First exception on row 0; first error: FIELD_CUSTOM_VALIDATION_EXCEPTION, Please contact Risk team for validation that the Merchant Application has been Approved: [StageName]
Stack Trace	Class.MerchOppsRecordsTest.MO: line 42, column 1

@IsTest
public class MerchOppsRecordsTest { 
 
    public static testmethod void MO() {

  Account a=new account();
  a.name='testaccount';
  a.website='www.test.com';
  a.Base_Rate_Program__c='2.9%';
  a.socpl__Billing_Country__c='USA';
  a.Company_Description__c='testing';
  a.Incumbent_Processer__c='Startup';
  a.Current_Integration_Type__c='Hosted Pages';
  a.Primary_Investor_s_VC_s_Name_s__c='Self funded';
  a.Approval_Stage__c='Approved';
  
  //put all other mandatory fields on account
  insert a;
  
    Merchant_Application__c  ma=new Merchant_Application__c ();
  ma.name='testaccount-1';
  ma.Account_Name__c=a.id;
  ma.Merchant_Application_Status__c='Approved';
  ma.MA__c='null';
  ma.Principal_First_Name__c='Bruce';
  ma.Principal_Last_Name__c='Wayne';
  ma.Completed__c='Completed';
  
  //put all other mandatory fields on Merchant_Application__c object
  insert ma;
  
  Opportunity o=new opportunity ();
  o.name='opp1';
  o.stagename='Signed';
  o.closedate=date.parse('06/23/2014');
  o.Go_Live_Date__c=date.parse('07/16/2014');
  o.P_T_Date__c=date.parse('10/31/2014');
  o.Next_Step__c='test';
  o.type='New Business';
  o.leadsource='Get Started';
  
  insert o;
  
  MerchOpps__c mo=new MerchOpps__c ();
  mo.name='Work';
  mo.ChildofMA__c=ma.id;
  mo.ChildofOpp__c=o.id;
  
  insert mo;  
  
  ma = [select name from merchant_application__c where id = :ma.id];
update ma;

  o = [select name from Opportunity where id =:o.id];
  update o;
}
}

Here is the trigger I am trying to get code coverage for. When I turn off validation rules I get 75%

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trigger MerchOppsRecords on Merchant_Application__c (after update){     Set<Id> accountIds = new Set<Id>();     Map<Id,Opportunity> accountOpportunityMap = new Map<Id,Opportunity>();     for(Merchant_Application__c ma : Trigger.new){         accountIds.add(ma.Account_Name__c);      }             for(Opportunity opp : [Select Id, Name, AccountId from Opportunity where AccountId = :accountIds]){         accountOpportunityMap.put(opp.AccountId,opp);     }          List<MerchOpps__c> mOps = new List<MerchOpps__c>();           for(Merchant_Application__c ma : Trigger.new){                  if(accountOpportunityMap.containsKey(ma.Account_Name__c)){             MerchOpps__c mo = new MerchOpps__c(ChildofOpp__c = accountOpportunityMap.get(ma.Account_Name__c).Id, ChildofMA__c = ma.ID);             mOps.add(mo);          }     }         insert mOps;        }