add start and end date and test for null entries

app/Plan/UseCases/CreatePlan.php

@@ -42,6 +42,14 @@ class CreatePlan
             throw new BadRequestException('name is required');
         }
 
+        if ($request->dateStart === null) {
+            throw new BadRequestException('date start is required');
+        }
+
+        if ($request->dateEnd === null) {
+            throw new BadRequestException('date end is required');
+        }
+
         $userId = $request->userId;
         $user = $this->userRepo->find($userId);
         if ($user === null) {

app/Plan/UseCases/CreatePlanRequest.php

@@ -8,5 +8,7 @@ class CreatePlanRequest
         public ?int $userId,
         public ?int $textId,
         public ?string $name,
+        public ?string $dateStart,
+        public ?string $dateEnd,
     ) {}
 }