anchor.diff:  
   let readText (response : HttpResponseMessage) =
       response.Content.ReadAsStringAsync()
  -    |> runTask
   
   let shouldEqual expected actual =
       Assert.Equal(expected, actual)
  
positive.code:     request
  
  let makeRequest (client : HttpClient) (request : HttpRequestMessage) =
      use server = new TestServer(createHost())
      use client = server.CreateClient()
      request
      |> client.SendAsync
      |> runTask
  
  let ensureSuccess (response : HttpResponseMessage) =
      if not response.IsSuccessStatusCode
      then response.Content.ReadAsStringAsync() |> runTask |> failwithf "%A"
      else response
  
  let isStatus (code : HttpStatusCode) (response : HttpResponseMessage) =
      Assert.Equal(code, response.StatusCode)
  
negative.code: // Helper functions
  // ---------------------------------
  
  let get (client : HttpClient) (path : string) =
      path
      |> client.GetAsync
  
  let createRequest (method : HttpMethod) (path : string) =
      let url = "http://127.0.0.1" + path
  