Testing Image Upload with Intervention image bundle

I wrote a test for testing the uploaded image. When I'm testing the API with Postman and Insomnia it works well. But the test fail because the intervention image returns an error. If I switch from intervention image to normal save it works. But I want to use it for resizing images.

This is the line which returns errors:

Image::make($request->file('profile_picture'))->fit(250, 250)->save($path.$fileNameToStore);

The error:

Can't write image data to path (storage/profile_pictures/avatarForTesting_1588586805.jpg)

Test

 public function testIfUsersCanUploadFirstAvatar(){

          $this->withoutExceptionHandling();

        // Create user
        $user = factory(User::class)->create();
        $trainee = factory(Trainee::class)->create(['trainee_id' => $user->id]);
        
        // Login user
        $this->actingAs($user);
        
        // Update profile with filled file upload request
        $response = $this->json('POST','http://api.'.env('APP_URL').'/profile/update/avatar/'.$user->id, 
            [
                'profile_picture' => UploadedFile::fake()->image('avatarForTesting.jpg', 200)
            ]);
        
        
        // Check if the avatar path is updated regarding uploaded picture
        $getImageName = User::find($user->id);
        $this->assertEquals(substr($getImageName->profile_picture, 0, -15), 'avatarForTesting');
    }

Upload Image

public function saveProfilePicture(Request $request, $userId)
     {
         $request->validate([
             'profile_picture' => 'required|image|mimes:jpeg,png,jpg,gif,svg|max:5120',
         ],
 
         ['Please select an avatar before trying to upload',]
     );

         //Users avatar uploading
         if ($request->hasFile('profile_picture')) {
             // Get filename with the extension
             $filenameWithExt = $request->file('profile_picture')->getClientOriginalName();
             // Get just filename
             $filename = pathinfo($filenameWithExt, PATHINFO_FILENAME);
             // Get just ext
             $extension = $request->file('profile_picture')->getClientOriginalExtension();
             // Filename to store
             $fileNameToStore= $filename.'_'.time().'.'.$extension;
 
             //Reduce the size of the image and upload image
             $path = 'storage/profile_pictures/';
            // $path = $request->file('profile_picture')->storeAs('storage/profile_pictures', $fileNameToStore);
             Image::make($request->file('profile_picture'))->fit(250, 250)->save($path.$fileNameToStore);
         } else {
             $fileNameToStore = 'no_profile_picture.jpg';
         }

Thank you in advance.