How to use Route Model Binding while testing Laravel App?

Hello, i want to use model binding inside my testing file. Test looks like that:

public function testAdminOfPartyCanAttachUserToRole()
  {
      $this->seed(PermissionsSeeder::class);
      // GIVEN
      $party = Party::factory()->create();
      $user = User::factory()->create();
      $otherUser = User::factory()->create();
      $party->users()->attach([$user->id, $otherUser->id]);

      session(['party_id' => $party->id]);
      setPermissionsTeamId(session('party_id'));

      $role = Role::where('party_id', $party->id)
      ->where('name', 'Administratorzy')
      ->where('system_role', true)->first();

      $user->assignRole($role);
  
      // WHEN
      $result = $this->actingAs($user)->withMiddleware(['bindings'])->post("api/party/{$party->id}/roles/{$role->id}/attachUsers", [
        'user' => $otherUser,
        'role' => $role, 
      ]);
  
      // THEN
      $result->assertOk(); 
      $this->assertDatabaseHas('model_has_roles', [
        'model_type' => 'App\Models\User',
        'role_id' => $role->id,
        'model_id' => $otherUser->id,
        'party_id' => $party->id,
      ]);
  }

My route looks like that:

    Route::group([
        'middleware' => [
            "throttle:120, 0.5",
        ],
        'prefix' => 'roles'
    ], function ($router) {
        Route::post('/', [RoleController::class, 'create']);
        Route::get('/', [RoleController::class, 'index']);
        Route::patch('/{role}', [RoleController::class, 'update']);
        Route::delete('/{role}', [RoleController::class, 'delete']);
        Route::post('/{role}/attachUsers', [RoleController::class, 'attachUsers'])->name('attach.users');
    });

And my controller function looks like that:

    /**
     * Attach users to specific role
     *
     * @param  Request $request
     * @return \Illuminate\Http\Response
     */
    public function attachUsers(Request $request, Role $role)
    {
        $user = $request->user;
        dump($role);
        $user->assignRole('Administratorzy');

        return response(Response::HTTP_OK);
    }

I am getting error : TypeError: App\Http\Controllers\RoleController::attachUsers(): Argument #2 ($role) must be of type Spatie\Permission\Models\Role, string given, called in /app/api/vendor/laravel/framework/src/Illuminate/Routing/Controller.php on line 54 and defined in /app/api/app/Http/Controllers/RoleController.php:72 So.. i need help with using model binding while testing laravel app. That's all. Thank you. If there has already been a post on this topic before, I'm sorry but I couldn't find a good answer.