Test data fields return null in class but are populated in unit test

Question

I have a Visualforce page that is using a Controller extension. The extension's SOQL query is not returning the data that I expect when I run my unit tests, although it works inside of our sandbox. The query returns Account and Opportunity fields but when I filter on certain Account fields I end up with 0 rows returned.

• Account.Cohort__c is a Lookup to a custom object, Cohort__c
• Account.Enrollment_Status__c is a picklist

This query, in my extension class, returns 0 rows because the Account fields are null:

SELECT Account.Name, Account.Enrollment_Status__c, Cohort__c
FROM Opportunity
WHERE StageName = 'Enrolled' AND
AccountId IN 
(
 SELECT Id
 FROM Account
 WHERE Cohort__c = :chosenCohort.Id AND Enrollment_Status__c IN ('Enrolled','Graduated'))

The testing class:

@isTest
private class StudentDirectoryCohortExtensionTest{
    static testMethod void StudentDirectoryOnlyReturnsEnrolledAndGraduated_Test(){
        TestRecordSet db = new TestRecordSet();        

        // Present for helping debug SOQL in extension class
        List<Account> tempAccounts = [SELECT Name, Cohort__c, Enrollment_Status__c FROM Account WHERE Cohort__c = :db.cohorts[0].Id];
        System.Debug('Test after insert');
        for (Account acc: tempAccounts){
            System.Debug('Enrollment Status: ' + acc.Enrollment_Status__c);
        }

        Test.startTest();
        PageReference pageRef = Page.StudentDirectory;
        Test.setCurrentPageReference(pageRef);

        // Call Constructor
        ApexPages.StandardController sc = new ApexPages.standardController(db.cohorts[0]);
        StudentDirectoryCohortExtension myExtension = new StudentDirectoryCohortExtension(sc);

        Test.stopTest();

        // Count the number of items in cohortMembers
        // This Assert fails; expected 4, getting 0
        integer memberCount = myExtension.cohortMembers.size();
        System.assertEquals(db.NumberOfCohortStudents , memberCount);   
    }

    // Holds test data to be used during method testing.
    private class TestRecordSet{    
        private List<Account> accounts;
        private List<Opportunity> applications;
        private List<Cohort__c> cohorts;
        private List<Academic_Program__c> programs;

        // Gets the number of students in a cohort (Enrolled or Graduated).
        public integer NumberOfCohortStudents {get; private set;}

        public TestRecordSet(){  
            // Add an Academic Program for the test Cohort
            this.programs = new List<Academic_Program__c>{
                new Academic_Program__c(
                    name = 'Internet MBA: One-Year',
                    Program_name_long__c = 'Internet MBA: One-Year')                       
            };

            insert this.programs;

            // Setup the test cohort      
            this.cohorts = new List<Cohort__c>{
                new Cohort__c(
                    name = 'I1MBAS13',
                    Start_Date__c = System.Today(),
                    Academic_Program__c = this.programs[0].Id)
            };

            insert this.cohorts;

            // Setup the test accounts and assign them to our cohort
            RecordType studentRecordType = [SELECT Id FROM RecordType WHERE Name = 'Graduate Student'];
            this.accounts = new List<Account>{
                new Account(
                    FirstName = 'Enrolled',
                    LastName = 'Test',
                    Cohort__c = this.cohorts[0].Id,
                    Enrollment_Status__c = 'Enrolled',
                    RecordTypeId = studentRecordType.Id),
                new Account(
                    FirstName = 'Graduated',
                    LastName = 'Test',
                    Cohort__c = this.cohorts[0].Id,
                    Enrollment_Status__c = 'Graduated'),
                new Account(
                    FirstName = 'Withdrew',
                    LastName = 'Test',
                    Cohort__c = this.cohorts[0].Id,
                    Enrollment_Status__c = 'Withdrew'),
                new Account(
                    FirstName = 'Denied',
                    LastName = 'Test',
                    Cohort__c = this.cohorts[0].Id,
                    Enrollment_Status__c = '')
            };

            this.NumberOfCohortStudents = 2;
            insert this.accounts;

            // Configure our test applications
            this.applications = new List<Opportunity>{
                new Opportunity(
                    name='Enrolled Application',
                    Account = this.accounts[0],       
                    CloseDate = System.Today(),
                    StageName = 'Enrolled',       
                    Test_Score_Type_for_Admission__c = 'Exempt', 
                    Academic_Program__c = this.programs[0].Id),
                new Opportunity(
                    name='Graduated Application',
                    Account = this.accounts[1],        
                    CloseDate = System.Today(),
                    StageName = 'Enrolled',       
                    Test_Score_Type_for_Admission__c = 'Exempt', 
                    Academic_Program__c = this.programs[0].Id),
                new Opportunity(
                    name='Withdrawn Application',
                    Account = this.accounts[2],       
                    CloseDate = System.Today(),
                    StageName = 'Enrolled',       
                    Test_Score_Type_for_Admission__c = 'Exempt', 
                    Academic_Program__c = this.programs[0].Id),
                new Opportunity(
                    name='Denied Application',
                    Account = this.accounts[3],       
                    CloseDate = System.Today(),
                    StageName = 'Denied',       
                    Academic_Program__c = this.programs[0].Id)
            };

            insert this.applications; 
        }
    }
}

How is it that in my unit test these are populated but null for my extension?

** Update ** Provided the full testing class

Answer 1

The issue is with your Opportunity test data set up.

For example, you have Account = this.accounts[1] which sets the relationship field. You never actually set the Id field, though.

Try setting the AccountId field on the Opportunities instead. That should work.

AccountId = this.accounts[1].Id.