Test ASP.API controller with xUnit: can't assert Type

[HttpGet]
    public async Task<ActionResult<IEnumerable<RecipeDto>>> GetRecipes(
        [FromQuery] int pageNumber,
        [FromQuery] int pageSize,
        [FromQuery] string? title,
        [FromQuery] string? searchQuery)
    {
        try
        {
            (IEnumerable<Recipe> recipes, PaginationMetadata metadata) = await _recipeService.GetPage(pageNumber, pageSize, title, searchQuery);

            if (recipes is null || recipes.Any() == false)
            {
                _logger.LogInformationGetAll(nameof(Recipe));
                return NotFound();
            }

            IEnumerable<RecipeDto> response = recipes.Select(r => r.MapToRecipeDto());

            Response.Headers.Add("X-Pagination", JsonSerializer.Serialize(metadata));
            return Ok(response);
        }
        catch (Exception ex)
        {
            _logger.LogCriticalGetAll(nameof(Recipe), ex);
            return this.InternalErrorCustom();
        }
    }

 [Fact]
    public async Task GetRecipes_Empty_ReturnsNotFound()
    {

        // Arrange
        Tools.RecipeService recipeService = new Tools.RecipeService();
        RecipesController controller = new RecipesController(new NullLogger<RecipesController>(), recipeService);

        // Act
        ActionResult<IEnumerable<RecipeDto>> result = await controller.GetRecipes(1, 5, null, null);

        // Assert
        Assert.NotNull(result);
        Assert.IsType<ActionResult<IEnumerable<RecipeDto>>>(result);
        Assert.IsType<NotFoundResult>(result);
        Assert.Equal(controller.NotFound(), result);
    }