add find by user method in plan repo

tests/Fakes/FakePlanRepository.php

@@ -5,9 +5,13 @@ namespace Tests\Fakes;
 use App\Plan\CreatePlanDto;
 use App\Plan\Plan;
 use App\Plan\PlanRepository;
+use App\User\User;
 
 class FakePlanRepository implements PlanRepository
 {
+    /**
+     * @var Plan[]
+     */
     private array $existingPlans = [];
 
     public function create(CreatePlanDto $dto): Plan
@@ -37,4 +41,24 @@ class FakePlanRepository implements PlanRepository
             }
         );
     }
+
+    public function findByUser(User $user): array
+    {
+        $plans = array_filter(
+            $this->existingPlans,
+            function (Plan $plan) use ($user) {
+                return $plan->getUser()->getId() === $user->getId();
+            }
+        );
+        return array_map(
+            function (Plan $plan) {
+                return new Plan(
+                    id: $plan->getId(),
+                    name: $plan->getName(),
+                    user: $plan->getUser(),
+                );
+            },
+            $plans
+        );
+    }
 }