@Neha Aggrawal  : sorry can you help me?  SendEmail failed. First exception on row 0; first error: REQUIRED_FIELD_MISSING, Add a recipient to send an email.: [] I have this error


@IsTest
public class Test_BatchSendEmailNotification {
@testSetup
 static void setup() {
   
    List<Contact> contatti= new List<Contact>();
   Id RecordTypeResId = Schema.SObjectType.Account.getRecordTypeInfosByDeveloperName().get('Reseller').getRecordTypeId();
   Id RecordTypeWalletId = Schema.SObjectType.Wallet__c.getRecordTypeInfosByDeveloperName().get('Reseller_Wallet').getRecordTypeId();
   Id BillingEntityId = Schema.SObjectType.Account.getRecordTypeInfosByDeveloperName().get('Billing_Entity').getRecordTypeId();
   
   Account billingE = new Account(Name = 'Konnect Africa RDC', RecordTypeId = BillingEntityId, CurrencyISOCode = 'USD', Number_of_Terminal_Activated__c=1, timezone__c = 'Africa/Brazzaville');
        insert billingE;  
   
   //account di contatto 1 e 2
   Account acc=new Account(Name='Reseller',Notifications_Email__c=true,Account_Type__c='Reseller',RecordTypeId=RecordTypeResId,BillingEntity__c=billingE.Id);
   insert acc;
   Id account_resId = [SELECT id, Name From Account WHERE Name = 'Reseller'].id;
 
   
   //contatti 1 e 2
   Contact contact_res1 = new Contact(Main_Contact__c=true ,LastName = 'Res', AccountId= account_resId,email ='test23f456a71a213@test5s4sd.com',Notifications_Email__c=true,Contact_ext_Id__c ='b8280a1d',Preferred_Language__c='English'); 
   Contact contact_res2 = new Contact(LastName = 'Res2', AccountId= account_resId,email ='test23f456a71a213@test5s42d.com',Notifications_Email__c=true,Contact_ext_Id__c ='b8280a2d',Preferred_Language__c='English');   
   contatti.add(contact_res1);
   contatti.add(contact_res2);
   insert contatti;
     
   Id resellerId = [SELECT Id FROM Profile WHERE Name = 'Reseller Admin Basic' LIMIT 1].id;
   Id contact_resId1 = [SELECT id, LastName From Contact WHERE LastName = 'Res'].id;
   Id contact_resId2 = [SELECT id, LastName From Contact WHERE LastName = 'Res2'].id;
   
   //user 1
    User user_res = new User(LastName = 'ResTest', alias = 'restest', Email= 'resellerTest@gmail.com', Username = 'resellerTest@gmail.com'    ,ProfileId=resellerId  , ContactId=contact_resId1, TimeZoneSidKey='America/Los_Angeles', LocaleSidKey='en_US', EmailEncodingKey='ISO-8859-1', LanguageLocaleKey='en_US' );
    insert user_res;
     
   //user 2
    User user_res2 = new User(LastName = 'ResTest2', alias = 'restest2', Email= 'resellerTest2@gmail.com', Username = 'resellerTest2@gmail.com'    ,ProfileId=resellerId  , ContactId=contact_resId2, TimeZoneSidKey='America/Los_Angeles', LocaleSidKey='en_US', EmailEncodingKey='ISO-8859-1', LanguageLocaleKey='en_US' );
    insert user_res2;
    Id user_resId = [Select Id from User WHERE Profile.Name='Reseller Admin Basic' AND isActive=true LIMIT 1].Id;
   
   //wallet 1
      Wallet__c wallet_res = new Wallet__c(RecordTypeId = RecordTypeWalletId, Amount__c = 13, Threshold_Amount__c = 220, OwnerId = user_resId, Account__c= account_resId);   
    insert wallet_res;
      
     
    contact_res1.Preferred_Language__c='Francais';
     update contact_res1;
     
    contact_res2.Preferred_Language__c='English';
     update contact_res2;
     
 }

@isTest
    static void BatchSendEmailNotification(){  
   
       List<Wallet__c> listaw=[SELECT Id,Amount__c,Account__c,Account__r.Notifications_Email__c,Account__r.Name,Account__r.Account_Type__c,Account__r.BillingEntity__r.Name
                                         FROM Wallet__c
                                         WHERE  Account__c!= null AND Account__r.Notifications_Email__c=TRUE AND Account__r.Account_Type__c='Reseller'];
       
      System.debug('lista wallet: --_>' +listaw);
        
      List<Contact> listac=[SELECT id, Name, Account.Notifications_Email__c,Preferred_Language__c,
                                      AccountId, Email, main_contact__c
                                     FROM Contact 
                                     WHERE Name='Res' OR Name='Res2' OR Notifications_Email__c=true];
        
    
        Test.startTest();       
       
           Id batchJobId = Database.executeBatch(new BatchSendEmailNotification(),200);
          System.debug('inviata email');
        
        Test.stopTest();
    }         
}