HttpContext Null through Unit testing

Question

I have following piece of code to evaluate the IP address

 public string getIPAddress()
        {
            string IPAddress = string.Empty;
            String strHostName = HttpContext.Current.Request.UserHostAddress.ToString();
            IPAddress = System.Net.Dns.GetHostAddresses(strHostName).GetValue(0).ToString();
            return IPAddress;


        }

Now when I tried to implement unit testing for this method, it always throws error, null reference,

I could not change the actual method just for unit testing, is there any way to handle this...

Thanks

You may have a look at this [question](http://stackoverflow.com/questions/4379450/mock-httpcontext-current-in-test-init-method) which shows how to **mock a httpContext**. I think this would be a good solution in your situation! — Pilgerstorfer Franz, Jun 20 '16 at 13:27

score 1 · Answer 1 · answered Jun 20 '16 at 11:21

1

That is expected because HttpContext is not available in unit tests and unit tests run in their own context. You will need to have a way to mock/provide HttpContext to your unit tests.

answered Jun 20 '16 at 11:21

sam

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If I am not missing , then It need changes in actual method, which i don't want – Md. Parvez Alam Jun 20 '16 at 12:02

score 1 · Answer 2 · edited Jun 20 '16 at 11:38

1

if you would not use "HttpContext.Current.Request.UserHostAddress" direct - but through a wrapperclass or other mockable class instead, you could then mock the behaviour.

Here is an Example

you should probably mock System.Net.Dns.GetHostAddresses(strHostName).GetValue(0) as well, to get your Test independent of this Class too.

edited Jun 20 '16 at 11:38

neer

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answered Jun 20 '16 at 11:33

Tom Söhne

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score 0 · Answer 3 · answered Jul 11 '16 at 15:23

if you want to mock HTTPContext while unit testing you can use typemock as in the following example regarding you method:

[TestMethod,Isolated]
public void TestForHttpContext_willReturn123AsIP()
{
    // Arrange
    Program classUnderTest = new Program();
    IPAddress[] a = { new IPAddress(long.Parse("123")), new IPAddress(long.Parse("456")), new IPAddress(long.Parse("789")) };

    Isolate.WhenCalled(() => HttpContext.Current.Request.UserHostAddress).WillReturn("testIP");
    Isolate.WhenCalled(() => Dns.GetHostAddresses(" ")).WillReturn(a);

    // Act
    var res = classUnderTest.getIPAddress();

    // Assert
    Assert.AreEqual("123.0.0.0", res);
}

HttpContext Null through Unit testing

3 Answers3