Control Processes with Queueable Apex

Control Processes with Queueable Apex from (module - Asynchronous Apex)

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SOURCE CODE1: AddPrimaryContact

public class AddPrimaryContact implements Queueable
{
    private Contact c;
    private String state;
    public  AddPrimaryContact(Contact c, String state)
    {
        this.c = c;
        this.state = state;
    }
    public void execute(QueueableContext context)
    {
         List<Account> ListAccount = [SELECT ID, Name ,(Select id,FirstName,LastName from contacts ) FROM ACCOUNT WHERE BillingState = :state LIMIT 200];
         List<Contact> lstContact = new List<Contact>();
         for (Account acc:ListAccount)
         {
                 Contact cont = c.clone(false,false,false,false);
                 cont.AccountId =  acc.id;
                 lstContact.add( cont );
         }
         if(lstContact.size() >0 )
         {
             insert lstContact;
         }} }

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SOURCE CODE2: AddPrimaryContactTest

@isTest
public class AddPrimaryContactTest {
@isTest static void TestList()
     {
     List<Account> Teste = new List <Account>();
         for(Integer i=0;i<50;i++)
         {
             Teste.add(new Account(BillingState = 'CA', name = 'Test'+i));
         }
         for(Integer j=0;j<50;j++)
         {
             Teste.add(new Account(BillingState = 'NY', name = 'Test'+j));
         }
         insert Teste;
     Contact co = new Contact();
         co.FirstName='demo';
         co.LastName ='demo';
         insert co;
         String state = 'CA';
      AddPrimaryContact apc = new AddPrimaryContact(co, state);
          Test.startTest();
            System.enqueueJob(apc);
          Test.stopTest();
      } }