diff --git a/backend/tests/Feature/Set/EloquentSetRepositoryTest.php b/backend/tests/Feature/Set/EloquentSetRepositoryTest.php
new file mode 100644
index 0000000..bb4679f
--- /dev/null
+++ b/backend/tests/Feature/Set/EloquentSetRepositoryTest.php
@@ -0,0 +1,107 @@
+<?php
+
+namespace Tests\Feature\Set;
+
+use App\Set\CreateSetDto;
+use App\Set\SetRepository;
+use App\Shared\ValueObject\EmailAddress;
+use App\User\CreateUserDto;
+use App\User\User;
+use App\User\UserRepository;
+use Illuminate\Database\QueryException;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\DB;
+use Tests\TestCase;
+
+class EloquentSetRepositoryTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_it_creates_sets_with_their_creator(): void
+    {
+        $creator = $this->createUser('creator@example.com');
+        $set = app(SetRepository::class)->create(new CreateSetDto(
+            name: 'Bible',
+            creator: $creator,
+        ));
+
+        $this->assertGreaterThan(0, $set->getId());
+        $this->assertSame('Bible', $set->getName());
+        $this->assertSame($creator->getId(), $set->getCreator()->getId());
+        $this->assertDatabaseHas('sets', [
+            'id' => $set->getId(),
+            'name' => 'Bible',
+            'creator_id' => $creator->getId(),
+        ]);
+    }
+
+    public function test_it_lists_every_set_alphabetically(): void
+    {
+        $firstCreator = $this->createUser('first@example.com');
+        $secondCreator = $this->createUser('second@example.com');
+        $repository = app(SetRepository::class);
+        $repository->create(new CreateSetDto(
+            name: 'Fitness Program',
+            creator: $firstCreator,
+        ));
+        $repository->create(new CreateSetDto(
+            name: 'Bible',
+            creator: $secondCreator,
+        ));
+        $repository->create(new CreateSetDto(
+            name: 'Course',
+            creator: $firstCreator,
+        ));
+
+        $sets = $repository->all();
+
+        $this->assertSame(
+            ['Bible', 'Course', 'Fitness Program'],
+            array_map(function ($set): string {
+                return $set->getName();
+            }, $sets),
+        );
+        $this->assertSame(
+            $secondCreator->getId(),
+            $sets[0]->getCreator()->getId(),
+        );
+    }
+
+    public function test_it_rejects_duplicate_set_names(): void
+    {
+        $creator = $this->createUser('creator@example.com');
+        $repository = app(SetRepository::class);
+        $repository->create(new CreateSetDto(
+            name: 'Bible',
+            creator: $creator,
+        ));
+
+        $this->expectException(QueryException::class);
+
+        $repository->create(new CreateSetDto(
+            name: 'Bible',
+            creator: $creator,
+        ));
+    }
+
+    public function test_it_prevents_deleting_a_set_creator(): void
+    {
+        $creator = $this->createUser('creator@example.com');
+        app(SetRepository::class)->create(new CreateSetDto(
+            name: 'Bible',
+            creator: $creator,
+        ));
+
+        $this->expectException(QueryException::class);
+
+        DB::table('users')->where('id', $creator->getId())->delete();
+    }
+
+    private function createUser(string $email): User
+    {
+        return app(UserRepository::class)->create(new CreateUserDto(
+            email: new EmailAddress($email),
+            passwordHash: 'hashed-password',
+        ));
+    }
+}
diff --git a/backend/tests/Unit/Set/SetTest.php b/backend/tests/Unit/Set/SetTest.php
new file mode 100644
index 0000000..ed7d75d
--- /dev/null
+++ b/backend/tests/Unit/Set/SetTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Tests\Unit\Set;
+
+use App\Set\Set;
+use App\Shared\ValueObject\EmailAddress;
+use App\User\User;
+use PHPUnit\Framework\TestCase;
+
+class SetTest extends TestCase
+{
+    public function test_it_exposes_its_identity_name_and_creator(): void
+    {
+        $creator = new User(
+            id: 7,
+            email: new EmailAddress('creator@example.com'),
+            passwordHash: 'hashed-password',
+        );
+        $set = new Set(
+            id: 42,
+            name: 'Bible',
+            creator: $creator,
+        );
+
+        $this->assertSame(42, $set->getId());
+        $this->assertSame('Bible', $set->getName());
+        $this->assertSame($creator, $set->getCreator());
+    }
+}