Write a Test Data Factory

LoanCalculationServiceTest, LoanValidationServiceTest, and LoanApplicationTriggerHandlerTest all construct Loan_Application__c-like data with similar values — a textbook case for Module 31's factory pattern, now genuinely justified by real duplication rather than a single, isolated example.

@isTest
public class LoanTestDataFactory {
    public static Loan_Application__c createApplication(Decimal amount, Decimal income, Decimal creditScore) {
        return new Loan_Application__c(
            Requested_Amount__c = amount,
            Annual_Income__c = income,
            Credit_Score__c = creditScore
        );
    }

    public static Loan_Application__c createQualifyingApplication() {
        return createApplication(10000, 50000, 720);
    }
}

1. @isTest — marks the class as test-only.
2. public class LoanTestDataFactory { — a shared factory.
3. public static Loan_Application__c createApplication(Decimal amount, Decimal income, Decimal creditScore) { — takes the values that actually vary between test scenarios.
4. return new Loan_Application__c( — builds the record.
5. Requested_Amount__c = amount, — the amount.
6. Annual_Income__c = income, — the income.
7. Credit_Score__c = creditScore — the credit score.
8. ); — closes the constructor call.
9. } — closes the method.
10. (blank line)
11. public static Loan_Application__c createQualifyingApplication() { — layers a sensible default on top for tests that just need any application that would pass.
12. return createApplication(10000, 50000, 720); — Module 22's constructor-parameter pattern applied to test data specifically.
13. } — closes the method.
14. } — closes the class.

@isTest
static void bulkApplicationsAllProcessCorrectly() {
    List<Loan_Application__c> applications = new List<Loan_Application__c>();
    for (Integer i = 0; i < 200; i++) {
        applications.add(LoanTestDataFactory.createQualifyingApplication());
    }

    Test.startTest();
    insert applications;
    Test.stopTest();

    // ... assertions unchanged ...
}

1. @isTest — marks the test method.
2. static void bulkApplicationsAllProcessCorrectly() { — the same test as before.
3. List<Loan_Application__c> applications = new List<Loan_Application__c>(); — unchanged.
4. for (Integer i = 0; i < 200; i++) { — unchanged.
5. applications.add(LoanTestDataFactory.createQualifyingApplication()); — only the data-construction line changed, now delegating to the factory.
6. } — closes the loop.
7. (blank line)
8. Test.startTest(); — unchanged.
9. insert applications; — unchanged.
10. Test.stopTest(); — unchanged.
11. (blank line)
12. // ... assertions unchanged ... — same test, same assertions, same result — exactly the "behavior unchanged, structure clearer" outcome from every refactoring lesson since Module 12.
13. } — closes the test method.