Quiz Answers – Chapter 4

Preface – This post is part of the Write Your First Intermediate Trigger series.
View Chapter 4 quiz questions without the answers!

Chapter 4 Questions:

1. Without SOQL, what fields are available for each record entering a trigger?

2. What character must be placed before every Apex variable used in a SOQL query?

3. What does an error look like to the end user when adding an error to a record using the .addError() method?

4. Why shouldn’t a developer query for production records in a test class?

5. Why should every test class use System.assertEquals(), even if your code works 100% of the time?

6. What’s the negative test case for a trigger that divides the Amount by the number of days until the Close Date?

7. Which is the correct way of using System.assertEquals()?
System.assertEquals(‘English Bulldog’, favoriteDog);
System.assertEquals(favoriteDog, ‘Toy Poodle’);

Chapter 4 Practice Trigger
Write a trigger on Leads that checks to see if another Lead or Contact has the exact same name. If so, populate a “Potential Lead Duplicate” or a “Potential Contact Duplicate” field. Don’t forget the test class!

trigger DetectDupes on Lead (before insert, before update) {
  for (Lead l : Trigger.new) {
    if (l.FirstName != null && l.LastName != null) {
      List<Lead> dupeLeads = [SELECT Id FROM Lead
                               WHERE FirstName = :l.FirstName
                                 AND LastName  = :l.LastName
                                 AND Id != :l.Id];      
      if (dupeLeads.size() > 0) {
        l.Potential_Lead_Dupe__c = dupeLeads[0].Id;
      } else {
        l.Potential_Lead_Dupe__c = null;
      } 
    
      List<Contact> dupeCts = [SELECT Id FROM Contact
                                WHERE FirstName = :l.FirstName
                                  AND LastName  = :l.LastName];
      if (dupeCts.size() > 0) {                                 
        l.Potential_Contact_Dupe__c = dupeCts[0].Id;        
      } else {
        l.Potential_Contact_Dupe__c = null;
      }                                         
    }
  }
}

@isTest 
public class TestDetectDupes {
  static testMethod void testDetectDupes() {
    Lead lead1 = new Lead();
    lead1.FirstName = 'Frodo';
    lead1.LastName  = 'Baggins';
    lead1.Company   = 'Shire';
    insert lead1;
    
    Contact ctc1 = new Contact();
    ctc1.FirstName = 'Frodo';
    ctc1.LastName  = 'Baggins';
    insert ctc1;
    
    Lead dupe = new Lead();
    dupe.FirstName = 'Frodo';
    dupe.LastName  = 'Baggins';
    dupe.Company   = 'Shire';
    insert dupe;
    
    dupe = [SELECT Id, Potential_Lead_Dupe__c, 
                   Potential_Contact_Dupe__c 
            FROM Lead 
            WHERE Id = :dupe.Id];
    System.assertEquals(lead1.Id, dupe.Potential_Lead_Dupe__c);
    System.assertEquals(ctc1.Id, dupe.Potential_Contact_Dupe__c);
    
    dupe.FirstName = 'Bilbo';
    dupe.LastName  = 'Baggins';
    update dupe;
    
    dupe = [SELECT Id, Potential_Lead_Dupe__c, 
                   Potential_Contact_Dupe__c 
            FROM Lead 
            WHERE Id = :dupe.Id];
    System.assertEquals(null, dupe.Potential_Lead_Dupe__c);
    System.assertEquals(null, dupe.Potential_Contact_Dupe__c);
  }
}