Moq httpclient returning empty string the second time

Question

I currently have code like:

var fieldBoundary = Properties.Resources.TestFieldBoundary;

httpClient.Setup(
    x =>
        x.GetAsync(It.Is<Uri>(url => url.AbsoluteUri == APIUrl.AbsoluteUri + <my url>)))
    .Returns(
        Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)
        {
            Content = new StringContent(Encoding.Default.GetString(fieldBoundary))
        }));

The first time through, using this mock http client I get the response that I expect. However when I call the same URL with the same mock object a second time I get a successful response but the response is an empty string or zero length byte array. Ideas on how this could be Moq'd differently?

Nkosi Nkosi · Accepted Answer · 2016-09-02T13:13:54

Change the Returms to use a function instead.

httpClient
    .Setup(x => x.GetAsync(It.Is<Uri>(url => url.AbsoluteUri == APIUrl.AbsoluteUri + <my url>)))
    .Returns(() => Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK) {
            Content = new StringContent(Encoding.Default.GetString(fieldBoundary))
        })
    );

it will call the function every time you make a call to the mocked method instead of returning the same instance on repeated calls. That is why when you made the call the second time the string content stream pointer was already at the end.

Moq httpclient returning empty string the second time

1 Answers