// ✅ GOOD: Bulkified Trigger Handler
public class AccountTriggerHandler {
    public static void updateRelatedContacts(List newList) {
        // Query once outside loop
        Map accMap = new Map(newList);
        List contactsToUpdate = new List();
        
        for (Contact con : [SELECT Id, AccountId FROM Contact WHERE AccountId IN :accMap.keySet()]) {
            con.AccountId = accMap.get(con.AccountId).Id;
            contactsToUpdate.add(con);
        }
        
        if (!contactsToUpdate.isEmpty()) {
            try {
                update contactsToUpdate; // Single DML
            } catch (Exception e) {
                System.debug(e.getMessage());
            }
        }
    }
}

// ✅ GOOD: SOQL with Security Enforcement
List accounts = [SELECT Id, Name FROM Account WITH SECURITY_ENFORCED];

// ✅ GOOD: Test Class
@isTest
public class AccountTest {
    @testSetup
    static void setup() {
        Account acc = new Account(Name = 'Test');
        insert acc;
    }
    
    @isTest
    static void testBulkify() {
        List testAccounts = new List();
        for (Integer i = 0; i < 200; i++) {
            testAccounts.add(new Account(Name = 'Bulk' + i));
        }
        
        Test.startTest();
        insert testAccounts;
        Test.stopTest();
        
        List results = [SELECT Id FROM Account WHERE Name LIKE 'Bulk%'];
        System.assertEquals(200, results.size());
    }
}