@isTest
public class ContactTriggerHandlerTest {

    //Test Setup
    //Create 1 test User
    //Create 1 contact records and assign to that test user. Insert the contact record
    //Create a list of 200 Contact Duplicate Records
    //Please note that the reason why we are creating so many duplicate records is to ensure that the trigger is bulkified
    //Start testing using: System.Test.startTest(); method
    //Use Database.insert(List <sObject>, boolean); to insert the second contact.
    //Make sure boolean above is set to false to prevent exception thrown when testing 
    //We are using Database method to retrieve the duplicate error message through its Database.SaveResults counterpart.
    //Pass the 200 duplicate contacts into the method we are testing: ContactTriggerHandler.dupContactError(List <Contract> newTrigCon); 
    //End testing using - System.Test.stopTest();  method
    //Evaluate Test Results
    //Use System assert method to evaluate that there still only exist 1 contact records and not 201 records
    //If the code worked, it should have prevented the 200 contacts from being created since they were duplicates
    //Iterate through the Database.SaveResults received and ensure that the error message received is equivalent to the error message we specified
    
    
    //TEST CODE STARTS HERE!
    
    @isTest static void dupContactErrorTest() {
        
     	   //Create test User
           User testUsr = new User(LastName = 'LastName Test',
                                  Alias = 'UsrR',
                                  Email = 'ClasstestReg@curious-fox.com',
                                  Username = 'ClasstestReg@test.com',
                                  CommunityNickname = 'ClassTestReg',
                                  ProfileId = [SELECT Id from Profile WHERE Name = 'Standard User' LIMIT 1].id,
                                  FirstName = 'Test Reg',
                                  TimeZoneSidKey = 'America/Los_Angeles', 
                                  LocaleSidKey = 'en_US',
                                  EmailEncodingKey = 'UTF-8', 
                                  LanguageLocaleKey = 'en_US');     
        
        
        insert testUsr;
        
        //Create ID variable to hold record type
        ID recType = Schema.SObjectType.Contact.getRecordTypeInfosByName().get('Contact').getRecordTypeID();
        
        
        //Create a contact and assign test user to it
        Contact testCon = new Contact(LastName = 'LastCon Test',
                                      Quater_Year__c = '',
                                      Month__c = 'Month 1',
                                      Assignedto__c = testUsr.id//,
                                      RecordTypeID = recType;
                                      );
        
        insert testCon;
        
        //Create list to hold duplicate Contacts
        List <Contact> dupCon = new List <Contact>();
        
        //Add 200 duplicate Contacts to the list. We are adding 200 to ensure code is bulkified.
        for (Integer i = 0; i < 200; i++) {
            
        dupCon.add(new Contact(LastName = 'LastCon Test',
                               Quater_Year__c = '',
                               Month__c = 'Month 1',
                               Assignedto__c = testUsr.id//,
                               RecordTypeID = recType;
                               ));    
              
        }
        
        //Tell System we are ready to test
        System.Test.startTest();
        
        //Insert 200 Duplicate Records
        List <Database.SaveResult> res = Database.insert(dupCon, false); //This tests the trigger
        ContactTriggerHandler.dupContactError(dupCon); //This tests the code in the methods
        
       
        //Tell system to stop Testing
        System.Test.stopTest();
        
        
        //Evaluate test results
        
        //Iterate through the errors received from trying to insert 200 duplicate records
        for (Database.SaveResult oneRes : res) {
            
            //If the insert was not successful,
            if(!oneRes.isSuccess()) {
                
                //Then iterate through the errors
                for (Database.Error oneEr : oneRes.getErrors()) {
                    
                    //This system check ensures that the error message received is the same as what the code specified
                    System.assertEquals('Duplicate Contact Error! This record already exists.', oneEr.getMessage());
                    
                }   
            }
        }
        
      //Create a list of all Contacts in the database.
      Contact[] allCon = [SELECT ID FROM Contact];
      
      //Due to the prevention of the duplicate rule, there should only exist one record contact still. Lets check
      System.assertEquals(true, allCon.size() == 1);  
        
    }
}