public void SetHeaderKeyValueWithMultipleMatchingHeaderNamesButOnlyOneMatchingKeyName() { HttpHeaders headers = CreateHeaders(); headers.Add("HEADER_NAME", "A=a1"); headers.Add("HEADER_NAME", "B=b1"); headers.Add("HEADER_NAME", "C=c1"); HttpHeadersUtilities.SetHeaderKeyValue(headers, "HEADER_NAME", "B", "b2"); EnumerableAssert.AreEqual(new[] { "A=a1", "C=c1", "B=b2" }, HttpHeadersUtilities.GetHeaderValues(headers, "HEADER_NAME")); Assert.IsTrue(HttpHeadersUtilities.ContainsHeaderKeyValue(headers, "HEADER_NAME", "B")); }