diff --git a/tests/Fakes/FakeUserRepository.php b/tests/Fakes/FakeUserRepository.php
index 2890de9..062cae8 100644
--- a/tests/Fakes/FakeUserRepository.php
+++ b/tests/Fakes/FakeUserRepository.php
@@ -15,7 +15,12 @@ class FakeUserRepository implements UserRepository
 
     public function find(int $id): ?User
     {
-        $user = $this->existingUsers[$id];
+        $user = array_find(
+            $this->existingUsers,
+            function (User $user) use ($id) {
+                return $user->getId() === $id;
+            }
+        );
         if ($user === null) {
             return null;
         }