public void SetHeader() { GetRequestBuilder <int, Greeting> b = new GetRequestBuilder <int, Greeting>(baseUrl); b.AddHeader("header1", "badvalue1"); b.SetHeader("header1", new List <string>() { "value1" }); b.AddHeader("header2", "value2"); b.AddHeader("header2", "value22"); CollectionAssert.AreEqual(new List <string>() { "value1" }, b.GetHeader("header1")); CollectionAssert.AreEqual(new List <string>() { "value2", "value22" }, b.GetHeader("header2")); }