Salesforce Platform dev 1 Apex trigger testing

Writing a test class for a trigger is equivalent to writing a test class for any apex class. Before you write a trigger you need to understand the working functionality of a trigger. In other words, what is triggering trigger is it before or after insert update. 

Also, it is not a good practice to write complex logic within a trigger. Separate the logic to the new class so that testing becomes easier. 

We are going to write a very basic trigger on contact object which will be before insert trigger and whose sole purpose is to append the last name with '-test' keyword.

Trigger Code

trigger ContactTrigger on Contact (before insert) 

{

  for(contact c : trigger.new)

  {

     c.lastname = c.lastname+'-test';

  }

}

Test class

@istest

public class ContactTriggerTest 

{

  @istest static void TestContactTrigger()

  {

      

      system.Test.startTest();

      contact c = new contact();

      c.lastname= 'Porter beer';

      insert c;

      

      integer contactcount = [select count() from contact ];

      system.assert(contactcount==1);

      

      system.Test.stopTest();

      

  }

}

Screenshot of code coverage of 100 per cent after the executing of a test class