我的控制器有一个单元测试，它断言在找不到模型实例时返回 HttpNotFoundResult。问题是，控制器中的实际代码按预期工作，但我的单元测试没有。将 ActionResult 转换为 HttpNotFoundResult 时，它返回 null，因此我的单元测试失败。
控制器代码：
public ActionResult Delete(int? id)
{
if(id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Forum forum = forumRepository.GetForumById(id.GetValueOrDefault());
if(forum == null)
{
return new HttpStatusCodeResult(HttpStatusCode.NotFound);
}
return View(forum);
}
测试方法：
[TestMethod]
public void GetDeleteShouldReturn404IfForumNotFound()
{
// Arrange
var forumRepository = Mock.Create<IForumRepository>();
Mock.Arrange(() => forumRepository.GetForums())
.Returns(new List<Forum>() {
new Forum { ForumId = 1, Title = "General Forum", Description = "Place to discuss general stuff", Sequence = 2 },
new Forum { ForumId = 2, Title = "Gaming", Description = "Let's talk about gaming", Sequence = 1 },
new Forum { ForumId = 3, Title = "Web Development", Description = "ASP.NET is pretty cool", Sequence = 3 }
}).MustBeCalled();
// Act
ForumController controller = new ForumController(forumRepository);
ActionResult result = controller.Delete(5) as HttpNotFoundResult;
// Assert
Assert.IsNotNull(result);
Assert.IsInstanceOfType(result, typeof(HttpNotFoundResult));
}
Assert.IsNotNull 失败。我还尝试了以下相同的结果：
HttpNotFoundResult result = controller.Delete(5) as HttpNotFoundResult;
这让我大吃一惊，因为我在几个示例中看到了几乎相同的代码：
有什么我做错了吗？
编辑：
问题是我没有嘲笑 GetForumById()，将测试代码更改为以下工作：
[TestMethod]
public void GetDeleteShouldReturn404IfForumNotFound()
{
// Arrange
var id = 10;
Forum forum = null;
var forumRepository = Mock.Create<IForumRepository>();
Mock.Arrange(() => forumRepository.GetForumById(id))
.Returns(forum)
.MustBeCalled();
// Act
ForumController controller = new ForumController(forumRepository);
var result = controller.Delete(id) as HttpNotFoundResult;
// Assert
Assert.IsNotNull(result);
Assert.IsInstanceOfType(result, typeof(HttpNotFoundResult));
}