如果您正在使用 Typemock，您可以这样做:

If you are using Typemock, you can do this:

Isolate.WhenCalled(()=>controller.HttpContext.Current.Session["UserID"])
.WillReturn("your id");

测试代码如下:

[TestMethod]
public void Retrieve_IndexTest()
{
    // Arrange
    const string expectedViewName = "Index";

    IndexController controller = new IndexController();
    Isolate.WhenCalled(()=>controller.HttpContext.Current.Session["UserID"])
    .WillReturn("your id");
    // Act
    var result = controller.Index() as ViewResult;

    // Assert
    Assert.IsNotNull(result, "Should have returned a ViewResult");
    Assert.AreEqual(expectedViewName, result.ViewName, "View name should have been {0}", expectedViewName);
}