I have a trigger for an Opportunity:

trigger SolutionEngineer on Opportunity (after insert, after update) {
    List<Trial__c> trialList = [select id, Opportunity_Name__c, Solutions_Engineer__c from Trial__c];
    for (Opportunity opp :trigger.new) {
        for (Trial__c trial : trialList) {
            if(opp.id == trial.Opportunity_Name__c && opp.CloseDate > System.Today().addMonths(-6) && opp.IsClosed != True && opp.Sales_Engineer__c != trial.Solutions_Engineer__c ) {
                trial.Solutions_Engineer__c = opp.Sales_Engineer__c;
                update trialList;
            }    
        }
    }
}

I have a test for this trigger:

public class testSolutionEngineer {

    static testMethod void TestSolutionEngineer(){
        User u1 = new User();
        User u2 = new User();

        Account testAcc = new Account (name='Test Account Name', billingcountry='United States', billingstate='MD');
        insert testAcc;

        Contact testCont= new Contact (lastname='lastname', Leadsource='Event', ContactStatus__c='Active', Role__c='--Unknown--', Account=testAcc);
        insert testCont;

        Opportunity testOpp = new Opportunity (name='Test Opportunity Name', stagename='Lead(1)', CloseDate=system.today(), Account=testAcc, Sales_Engineer__c=u1.Id);
        insert testOpp;

        Trial__c testTri = new Trial__c(Trial_Type__c='Hosted');
        testTri.Opportunity_Name__c=testOpp.Id;
        testTri.Trial_Start_Date__c=System.today();   
        testTri.Trial_End_Date__c=System.today()+ 1;
        testTri.Solutions_Engineer__c=u2.Id;

        insert testTri;        
        update testOpp;
    } 
}

When I run my test, I am only getting 66% code coverage for my trigger:

I did some tests and specifically, opp.Sales_Engineer__c != trial.Solutions_Engineer__c is evaluating as False. What is going on?

Attribution to: Di Zou

Possible Suggestion/Solution #1

Your users are not inserted, therefore u1.Id == u2.Id == null.

Attribution to: Jeremy Nottingham

Possible Suggestion/Solution #2

Try this :

Both of them work and gives a 100% coverage on the trigger

Approach 1: User object can be queried and when you try to create user and try to Insert 2 users you will end up having mixed_dml_operations Since you want a real test case where you need to verify 2 users you can pick 2 random users

public class testSolutionEngineer {

static testMethod void TestSolutionEngineer(){

user u1 = [select id from user where profile.name = 'System Administrator' limit 1]; user u2 = [select id from user where profile.name = 'Standard Platform User' limit 1];

    Account testAcc = new Account (name='Test Account Name', billingcountry='United States', billingstate='MD');
    insert testAcc;

    Contact testCont= new Contact (lastname='lastname', Leadsource='Event',  Account=testAcc);
    insert testCont;

    Opportunity testOpp = new Opportunity (name='Test Opportunity Name', stagename='Lead(1)', CloseDate=system.today(), Account=testAcc, Sales_Engineer__c=u1.Id);
    insert testOpp;
    custom_object__c testTri = new custom_object__c ();
    testTri.Opportunity__c=testOpp.Id;
    //testTri.Trial_Start_Date__c=System.today();   
    //testTri.Trial_End_Date__c=System.today()+ 1;
    testTri.Solutions_Engineer_look__c = u2.Id;

    insert testTri;     

    update testOpp;

} 

}

Approach 2: System.runas() The user info is submitted based on the running user chosen

public class testSolutionEngineer {

    static testMethod void TestSolutionEngineer(){
     profile p2 = [select id from profile where name = 'Standard Platform User'];
        UserRole r2 = [Select id from userrole where name='CEO'];
         User u2 = new User(alias = 'standu', email='standuser@testorg.com', 
            emailencodingkey='UTF-8', lastname='Testing', 
            languagelocalekey='en_US', 
            localesidkey='en_US', profileid = p2.Id, userroleid = r2.Id,
            timezonesidkey='America/Los_Angeles', 
            username='standuser@testorg.com');
// user u1 = [select id from user where profile.name = 'System Administrator' limit 1];
 // user u2 = [select id from user where profile.name = 'Standard Platform User' limit 1];

system.runas(u2){

Account testAcc = new Account (name='Test Account Name', billingcountry='United States', billingstate='MD');
            insert testAcc;

        Contact testCont= new Contact (lastname='lastname', Leadsource='Event',  Account=testAcc);
        insert testCont;

        Opportunity testOpp = new Opportunity (name='Test Opportunity Name', stagename='Lead(1)', CloseDate=system.today(), Account=testAcc, Sales_Engineer__c=u2.Id);
        insert testOpp;
        custom_object__c testTri = new custom_object__c ();
        testTri.Opportunity__c=testOpp.Id;
        //testTri.Trial_Start_Date__c=System.today();   
        //testTri.Trial_End_Date__c=System.today()+ 1;
        testTri.Solutions_Engineer_look__c = null;

        insert testTri;     

        update testOpp;
}
    } 

}

Attribution to: Rao
This content is remixed from stackoverflow or stackexchange. Please visit https://salesforce.stackexchange.com/questions/4422