diff --git a/src/Contract/ImportDataInterface.php b/src/Contract/ImportDataInterface.php
new file mode 100644
index 0000000..406ed76
--- /dev/null
+++ b/src/Contract/ImportDataInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace solid\Contract;
+
+interface ImportDataInterface
+{
+    public function importData(array $records): void;
+}
diff --git a/src/Contract/UserListInterface.php b/src/Contract/UserListInterface.php
new file mode 100644
index 0000000..4584a96
--- /dev/null
+++ b/src/Contract/UserListInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace solid\Contract;
+
+interface UserListInterface
+{
+    public function getActives(): array;
+}
diff --git a/src/DataImporter.php b/src/DataImporter.php
index 0011e38..5e01448 100644
--- a/src/DataImporter.php
+++ b/src/DataImporter.php
@@ -2,23 +2,23 @@
 
 namespace solid;
 
+use solid\Contract\ImportDataInterface;
 use solid\Loader\CsvLoader;
-use solid\Repository\AbstractRepository;
 
 class DataImporter
 {
-    private AbstractRepository $repository;
+    private ImportDataInterface $importer;
     private CsvLoader $loader;
 
-    public function __construct(AbstractRepository $repository, CsvLoader $loader)
+    public function __construct(ImportDataInterface $importer, CsvLoader $loader)
     {
-        $this->repository = $repository;
+        $this->importer = $importer;
         $this->loader = $loader;
     }
 
     public function import(): void
     {
         $records = $this->loader->loadFile();
-        $this->repository->importData($records);
+        $this->importer->importData($records);
     }
 }
diff --git a/src/Mailer.php b/src/Mailer.php
new file mode 100644
index 0000000..e822686
--- /dev/null
+++ b/src/Mailer.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace solid;
+
+use solid\Contract\UserListInterface;
+
+class Mailer
+{
+    private UserListInterface $userList;
+    
+    public function __construct(UserListInterface $userList)
+    {
+        $this->userList = $userList;
+    }
+
+    public function send(): int
+    {
+        $users = $this->userList->getActives();
+        $mails = 0;
+
+        foreach ($users as $user) {
+            // ...
+
+            $mails++;
+        }
+
+        return $mails;
+    }
+}
diff --git a/src/Repository/AbstractRepository.php b/src/Repository/AbstractRepository.php
index aaf442b..4601d11 100644
--- a/src/Repository/AbstractRepository.php
+++ b/src/Repository/AbstractRepository.php
@@ -6,8 +6,9 @@
 
 use PDO;
 use PDOException;
+use solid\Contract\ImportDataInterface;
 
-abstract class AbstractRepository
+abstract class AbstractRepository implements ImportDataInterface
 {
     protected PDO $db;
     
diff --git a/src/Repository/UsersRepository.php b/src/Repository/UsersRepository.php
index d612a52..a583d2b 100644
--- a/src/Repository/UsersRepository.php
+++ b/src/Repository/UsersRepository.php
@@ -4,9 +4,10 @@
 
 namespace solid\Repository;
 
+use solid\Contract\UserListInterface;
 use solid\Repository\AbstractRepository;
 
-class UsersRepository extends AbstractRepository
+class UsersRepository extends AbstractRepository implements UserListInterface
 {
     protected function beforeInserts(): void
     {
@@ -15,7 +16,7 @@ protected function beforeInserts(): void
 
     protected function insert(array $record): void
     {
-        $this->db->prepare('INSERT INTO users VALUES (?, ?, ?)')
+        $this->db->prepare('INSERT INTO users (id, login, fullname) VALUES (?, ?, ?)')
             ->execute($record);
     }
 
@@ -25,4 +26,9 @@ public function getCount(): int
 
         return (int) $data['nb'];
     }
+
+    public function getActives(): array
+    {
+        return $this->db->query('SELECT * FROM users WHERE active = 1')->fetchAll();
+    }
 }
diff --git a/tests/MailerTest.php b/tests/MailerTest.php
new file mode 100644
index 0000000..a0b45a5
--- /dev/null
+++ b/tests/MailerTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace tests;
+
+use PHPUnit\Framework\TestCase;
+use solid\Mailer;
+use solid\Repository\UsersRepository;
+
+class MailerTest extends TestCase
+{
+    public function testMailer(): void
+    {
+        $mailer = new Mailer(
+            new UsersRepository(TestsFacility::createDb())
+        );
+
+        $mailsSent = $mailer->send();
+
+        $this->assertSame(2, $mailsSent);
+    }
+}
diff --git a/tests/TestsFacility.php b/tests/TestsFacility.php
index 7b1ca6f..0fc6d94 100644
--- a/tests/TestsFacility.php
+++ b/tests/TestsFacility.php
@@ -35,7 +35,8 @@ private static function loadFixtures(PDO $db): void
         $db->exec('CREATE TABLE users (
             id TINYTEXT NOT NULL,
             login TINYTEXT NOT NULL,
-            fullname TINYTEXT NOT NULL
+            fullname TINYTEXT NOT NULL,
+            active TINYINT NOT NULL DEFAULT 1
         )');
     }
 }