You can refer this link An Introduction to Apex Code Test Methods

to start writing test classes.

You can refer this link An Introduction to Apex Code Test Methods

to start writing test classes.

Below I have tried to show you following things:

1. How to create setup data.

2. How to create user for which you will run the test scenarios.

   @isTest public class clsOpportunity10_Test{ @testSetup static void prepareControllerClassData() { //retrieve the profile information Map<String,Id> profileIdNameMap = TestUtil.prepareProfileIdNameMap();

   //create Executive user.
    User mbExecutiveUser = TestUtil.createUser('Executive', 'user', profileIdNameMap.get('Executive')); 
    System.runAs(mbExecutiveUser)
     {
         createOpportunities();            
     }      
   

   }

   // create an user for the test class public static User createUser(String firstName, String lastName, String profileId){ String sRandom = String.ValueOf(Integer.valueOf(math.rint(math.random()*1000000))); User newUser = new User( ProfileId = profileId, Firstname=firstName, Lastname=lastName, Username = firstName + sRandom + '@xyz.com',
   Alias = firstName.substring(0,2) + lastName.substring(0,2), Email=firstName + lastName + '@xyz.com', EmailEncodingKey='UTF-8', LanguageLocaleKey='en_US',
   LocaleSidKey='en_US', TimeZoneSidKey='America/Chicago' ); return newUser; }

   public static Map<String,Id> prepareProfileIdNameMap() { if(profileIdNameMap.isEmpty()) { List lstProfile = [SELECT Id, Name FROM Profile WHERE Name IN ()];

        for(Profile objProfile:lstProfile)
        {
            profileIdNameMap.put(objProfile.Name, objProfile.Id);
        }            
    }
    return profileIdNameMap;        
   

   }

   public static void createOpportunities() { List lstOpportunity = new List(); Opportunity oppty1 = new Opportunity(); oppty1.RecordTypeId= Schema.SObjectType.Opportunity.getRecordTypeInfosByName().get('Construction').getRecordTypeId(); oppty1.StageName = 'Needs Qualifying'; oppty1.Branch__c = '10 - Western PA'; //assign all the values to be respective attributes lstOpportunity.add(oppty1);

    //same way for other stages and branches create opportunity data.
    //and finally insert the list
    insert(lstOpportunity);
   

   }

   public static void updateOpportunities() { System.runAs(mbExecutiveUser) { //you will retrieve the opportunity record

        //update the record
   
        //put System.assert() to verify values
    }
   

   }}