public void BrowserUtilityTest() { var userAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.87 Safari/537.36"; var mockHttpRequest = new Mock <HttpRequest>(); mockHttpRequest.Setup(z => z.Headers["User-Agent"]) .Returns(userAgent); var result = BrowserUtility.GetUserAgent(mockHttpRequest.Object); Console.WriteLine(result); Assert.AreEqual(userAgent, result, true); }