Unable to fetch relationship data in apex test class for data created in @testSetup

Question

I created an account, a contact and a user then connected all 3 to create a test community user in a method annoted with @testsetup. I ran my test in context of the community user created previously in setup method. But in my test methods when I try to fetch any data from logged in user's account(previously created in set up method), its returning null. However, I am able to fetch data from the logged in user's contact record. Below is a dummy code for my use case:

@isTest
Public class example_test{

   @testSetup
   Public static void createTestData(){
      
      //INSERT ACCOUNT
      Account a = new Account (Name = 'abc', Status = 'Active');
      insert a;

      //INSERT CONTACT
      Contact con = new Contact(Accountid = a.id, FirstName = 'X', LastName = 'Y');
      insert con;

      INSERT COMMUNITY USER
      User u = new User(LastName = 'testLast', Contactid = con.id, username = '[email protected]', email= '[email protected]' ..... );
      insert u;
   }

   @isTest
   Public static void test_Method1() {
       User testUser = [SELECT id,FirstName,LastName,Username,Contact.LastName,Contact.Account.Name from User LIMIT 1];
       system.assertEquals('Y',testUser.contact.LastName);
       system.assertEquals('abc',testUser.contact.Account.Name);

   }
}

In the above test class, for 1st assert statement it passed where as for the 2nd assert statement it failed as actual outcome is null. This problem is not occuring if you insert test data inside test methods or calling any test factory method not annoted as @testsetup Has anyone faced this problem before. Is this a problem for @testsetup methods?

Answer 1

I am able to get the values in test scope too. So the theory might be like this.

There are some setup objects which can be queried from test class even if you have marked the test as SeeAllData as false. Documentation

So when you fire [SELECT id,FirstName,LastName,Username,Contact.LastName,Contact.Account.Name from User LIMIT 1] it is not guaranteed that you will get the user which you created above.

To do that you need to add something in where clause.

[SELECT id,FirstName,LastName,Username,Contact.LastName,Contact.Account.Name from User where username = '[email protected]'].

Try adding this and check if the issue persists.