How to mock HttpRequestMessage with Moq

I'm working on a web Api. It's an ASP.NET application. I need to create a mock for the method CreateResponse(HttpStatusCode statusCode, T value) of HttpRequestMessage class. But every time I execute my test and get the exception

Test Name:  RHT.Tests.Controllers.AccountControllerTests.Can_login_with_valid_credentials
Test FullName:  RHT.Tests.Controllers.AccountControllerTests.Can_login_with_valid_credentials
Test Source:    Controllers\AccountControllerTests.cs : line 23
Test Outcome:   Failed
Test Duration:  0:00:01.028
Result StackTrace:

at Moq.Mock.ThrowIfSetupExpressionInvolvesUnsupportedMember(Expression setup, MethodInfo method) in C:\projects\moq4\src\Moq\Mock.cs:line 755

at Moq.Mock.SetupNonVoidPexProtected(Mock mock, LambdaExpression expression, Condition condition) in C:\projects\moq4\src\Moq\Mock.cs:line 433

at Moq.PexProtector.Invoke[T1,T2,T3,TResult](Func4 function, T1 arg1, T2 arg2, T3 arg3) in C:\projects\moq4\src\Moq\PexProtector.cs:line 38    at Moq.Mock.SetupNonVoid(Mock mock, LambdaExpression expression, Condition condition) in C:\projects\moq4\src\Moq\Mock.cs:line 421    at Moq.Mock1.Setup[TResult](Expression`1 expression) in C:\projects\moq4\src\Moq\Mock.Generic.cs:line 317

at RHT.Tests.Controllers.AccountControllerTests.Can_login_with_valid_credentials() in C:\Users\ttong\source\repos\RedHawkTestPlan\RHT.Tests\Controllers\AccountControllerTests.cs:line 51

Result Message: System.NotSupportedException : Invalid setup on an extension method: m => m.CreateResponse<string>(HttpStatusCode.OK, “value”)

The test

        Mock<IAuthProvider> auth = new Mock<IAuthProvider>();

auth.Setup(m => m.CreateEncryptedCookieValue(

It.IsAny<bool>(), It.IsAny<string>()))

.Returns(“my_ticket”);

    Mock&lt;HttpRequestMessage&gt; req = new Mock&lt;HttpRequestMessage&gt;();
    req.Setup(m =&gt; m.CreateResponse(
        HttpStatusCode.OK, "value"))
        .Returns(new HttpResponseMessage(HttpStatusCode.OK));

The test method has 3 mock objects. But only the HttpRequestMessage is fail to initialize. Any idea why it doesn’t work?

#c-sharp #asp.net