Question

I’m using Moq to create a Mock<HttpResponseBase> to test an FileResult I’m creating for my MVC2 application.

In the WriteFile(HttpResponseBase response) method of the FileResult, I have the following code at the end:

// Write the final output with specific encoding.
response.OutputStream.Write(output, 0, output.Length);
response.AppendHeader("Content-Encoding", encoding);

It will use utf-8 or gzip depending on the encoding from the request’s Accept-Encoding header.

So then in my test, I setup my Mock<HttpResponseBase> like so:

var mockResponse = new Mock<HttpResponseBase>();
mockResponse.Setup(r => r.OutputStream).Returns(new MemoryStream());
mockResponse.Setup(r => r.Headers).Returns(new NameValueCollection());

But when I actually check that the header has been set, Content-Encoding always returns null:

var response = mockResponse.Object;
Assert.AreEqual("utf-8", response.Headers["Content-Encoding"]);

The weird thing is that the OutputStream gets the data written to it and I can assert that it’s writing the correct value.

The odd thing is that when I actually debug the FileResult in a web project, the header is properly sent.

Does anyone have some insight to this? I can provide more code if necessary.

Answer 1

I ended up just mocking the AppendHeader method to forcefully add the header to the HttpResponseBase‘s headers:

mockResponse
    .Setup(r => r.AppendHeader(It.IsAny<string>(), It.IsAny<string>()))
    .Callback((string k, string v) => mockResponse.Object.Headers.Add(k, v));

I suspect that there is something further down inside the call of AppendHeader that doesn’t like adding headers without an actual HttpResponseBase in place.

If there is a better idea, feel free to suggest. Hope this helps someone in the future.