我通常把它分成两部分:
- 测试控制器在模型有效和无效时是否正确运行。
- 测试模型与规则引擎的组合是否产生正确的错误消息。
基本原理是,当控制器是否正确地处理错误,并且模型本身正确验证时,应用程序将正确地运行。测试设置也将更简单。
在帖子的最简单情况下,我们可能希望控制器在一切正常时重定向到结果页面,但在出现验证错误时重新显示相同的视图:
[TestClass]
public class Maintaining_todo_list
{
private TodoController controller;
[TestInitialize]
public void Setup()
{
controller = new TodoController {ControllerContext = new ControllerContext()};
}
[TestMethod]
public void Valid_update_should_redirect_to_list()
{
var result = controller.Edit(1, new TodoItem {Text = "todo"});
result.ShouldRedirectTo("list");
}
[TestMethod]
public void Invalid_update_should_display_same_view()
{
var result = controller.Edit(1, new TodoItem {Text = ""});
result.ShouldDisplayDefaultView();
}
}
该模型可能会以各种方式失败并显示不同的消息:
[TestClass]
public class Validating_todo_item
{
[TestMethod]
public void Text_cannot_be_empty()
{
var todo = new TodoItem {Text = ""};
todo.ShouldContainValidationMessage("Text cannot be empty");
}
[TestMethod]
public void Text_cannot_contain_more_than_50_characters()
{
var todo = new TodoItem { Text = new string('a', 51) };
todo.ShouldContainValidationMessage("Text cannot contain more than 50 characters");
}
[TestMethod]
public void Valid_items()
{
new TodoItem { Text = new string('a', 1) }.ShouldBeValid();
new TodoItem { Text = new string('a', 50) }.ShouldBeValid();
}
}
(为了完整起见,这里是测试助手)
internal static class AssertionHelpers
{
public static void ShouldRedirectTo(this ActionResult result, string action)
{
var redirect = result as RedirectToRouteResult;
Assert.IsNotNull(redirect);
Assert.AreEqual(action, redirect.RouteValues["action"]);
Assert.IsNull(redirect.RouteValues["controller"]);
}
public static void ShouldDisplayDefaultView(this ActionResult result)
{
var view = result as ViewResult;
Assert.IsNotNull(view);
Assert.AreEqual("", view.ViewName);
}
public static void ShouldContainValidationMessage(this TodoItem todo, string message)
{
var context = new ValidationContext(todo, null, null);
var results = new List<ValidationResult>();
Validator.TryValidateObject(todo, context, results, true);
var errors = results.Select(result => result.ErrorMessage);
foreach (var error in errors)
{
Console.Out.WriteLine(error);
}
Assert.IsTrue(errors.Contains(message));
}
public static void ShouldBeValid(this TodoItem todo)
{
var context = new ValidationContext(todo, null, null);
var results = new List<ValidationResult>();
var isValid = Validator.TryValidateObject(todo, context, results, true);
Assert.IsTrue(isValid);
}
}