测试 .NET Core 控制器视图组件

Question

在.NET的核心，我们有在呼唤具有依赖注入ViewComponent，按照微软的文档模式的控制器操作在这里。如果我们有一个控制器动作返回这样的渲染视图：public class MyController : Controller{    private readonly IToDoContext _todoContext;    public MyController(IToDoContext todoContext)    {        _todoContext = todoContext;    }    public IActionResult IndexVC()    {        return ViewComponent("PriorityList", new { maxPriority = 3, isDone = false });    }}还有一个具有如下依赖注入的 ViewComponent：public class PriorityListViewComponent : ViewComponent{    private readonly ToDoContext db;    public PriorityListViewComponent(ToDoContext context)    {        db = context;    }    public async Task<IViewComponentResult> InvokeAsync(int maxPriority, bool isDone)    {        var items = await GetItemsAsync(maxPriority, isDone);        return View(items);    }    private Task<List<TodoItem>> GetItemsAsync(int maxPriority, bool isDone)    {        return db.ToDo.Where(x => x.IsDone == isDone && x.Priority <= maxPriority).ToListAsync();    }}我们如何在控制器动作单元测试中将 ToDoContext 注入到 ViewComponent 中？到目前为止， result.Model 始终为空，因为似乎没有办法将 ToDoContext db 注入控制器，然后再注入 ViewComponent。[Fact]public void Should_return_viewcomponent(){    var mockToDoContext = new Mock<IToDoContext>();    mockToDoContext.Setup(m => m.Get()).ReturnsAsync(new ToDoContext());    var sut = new MyController(mockToDoContext.Object);    var result = sut.PriorityListViewComponent("myparams") as ViewComponentResult;    // ToDoContext db is never set, so the result.Model is always null}

Answer 1

仅供参考：我认为微软的例子是错误的。一旦我将 View Component 更改为 View 并将数据从 View Component 代码中获取到后面并移到 Controller 中，那么一切都变得容易测试和实现 Bad Request 逻辑，等等。只需记住将 View Component 移出 View Component 目录，并在视图中将 layout 设置为 null。

控制器应该看起来更像这样：

public class MyController : Controller

{

    private readonly IToDoContext _db;

    public MyController(IToDoContext db)

    {

        _db = db;

    }

    public async Task<IActionResult> IndexVC("PriorityList", new { maxPriority, isDone = false })

        {

            if (string.IsNullOrWhiteSpace(maxPriority))

                return BadRequest($"maxPriority cannot be empty");

            var model = await InvokeAsync(maxPriority, isDone);

            if (model == null)

            {

                return BadRequest($"model not found");

            }

            return View(model);

        }

    public async Task<IViewComponentResult> InvokeAsync(

        int maxPriority, bool isDone)

        {

            var items = await GetItemsAsync(maxPriority, isDone);

            return View(items);

        }

        private Task<List<TodoItem>> GetItemsAsync(int maxPriority, bool isDone)

        {

            return _db.ToDo.Where(x => x.IsDone == isDone &&

                                 x.Priority <= maxPriority).ToListAsync();

        }

}

单元测试看起来像：

[Fact]

public void Should_return_viewcomponent()

{

    var mockToDoContext = new Mock<IToDoContext>();

    mockToDoContext.Setup(m => m.Get())

        .ReturnsAsync(new ToDoContext());

    var sut = new MyController(mockToDoContext.Object);

    var result = await sut.PriorityList("myparams") as ViewResult;

    result.Model.ShouldNotBeNull();

    var resultModel = result.Model as PriorityListModel;

    resultModel.ShouldNotBeNull();

    resultModel.Thing.ShouldBe("whatever");

}

Bad Request 单元测试看起来像这样（注意 BadRequestObjectResult）：

[Fact]

public async Task Should_return_bad_request_if_result_not_found()

{

    var mockToDoContext = new Mock<IToDoContext>();

    mockToDoContext.Setup(m => m.Get())

        .ReturnsAsync(null);

    var httpContext = new DefaultHttpContext();

    var sut = new MyController(mockToDoContext.Object)

    {

        ControllerContext = new ControllerContext { HttpContext = httpContext }

    };

    var result = await sut.PriorityList("myparams") as BadRequestObjectResult;

    result.ShouldNotBeNull();

    result.StatusCode.ShouldBe(400);

    result.Value.ShouldBe("model not found");

}