chore: import upstream snapshot with attribution

tests/fixtures/sample.cls

@@ -0,0 +1,55 @@
+public with sharing class AccountService {
+
+    private static final String DEFAULT_TYPE = 'Customer';
+
+    public interface Notifiable {
+        void notify(String message);
+    }
+
+    public enum AccountStatus { ACTIVE, INACTIVE, PENDING }
+
+    @AuraEnabled
+    public static List<Account> getAccounts(String accountType) {
+        return [SELECT Id, Name, Type FROM Account WHERE Type = :accountType];
+    }
+
+    @future
+    public static void updateAccountsAsync(List<Id> accountIds) {
+        List<Account> accounts = [SELECT Id FROM Account WHERE Id IN :accountIds];
+        for (Account acc : accounts) {
+            acc.Type = DEFAULT_TYPE;
+        }
+        update accounts;
+    }
+
+    @InvocableMethod(label='Create Account' description='Creates a new Account')
+    public static List<Id> createAccounts(List<String> names) {
+        List<Account> toInsert = new List<Account>();
+        for (String n : names) {
+            toInsert.add(new Account(Name = n));
+        }
+        insert toInsert;
+        List<Id> ids = new List<Id>();
+        for (Account a : toInsert) {
+            ids.add(a.Id);
+        }
+        return ids;
+    }
+
+    public static void deleteOldAccounts(Date cutoff) {
+        List<Account> old = [SELECT Id FROM Account WHERE CreatedDate < :cutoff];
+        delete old;
+    }
+
+    @isTest
+    static void testGetAccounts() {
+        List<Account> result = getAccounts('Customer');
+        System.assertNotEquals(null, result);
+    }
+
+    @isTest
+    static void testCreateAccounts() {
+        List<Id> ids = createAccounts(new List<String>{'Test'});
+        System.assertEquals(1, ids.size());
+    }
+}