public void AddVersionInfo(string productName, string productVersion) { var dataSender = new SpanDataSender(new TelemetryConfiguration().WithApiKey("123456")); var fieldInfo = dataSender.GetType().GetField("_userAgent", BindingFlags.NonPublic | BindingFlags.Instance); var userAgentValueBefore = fieldInfo.GetValue(dataSender); var expectedUserAgentValue = userAgentValueBefore?.ToString(); if (!string.IsNullOrEmpty(productName) && !string.IsNullOrEmpty(productVersion)) { expectedUserAgentValue = userAgentValueBefore + " " + $@"{productName}/{productVersion}"; } dataSender.AddVersionInfo(productName, productVersion); var userAgentValueAfter = fieldInfo.GetValue(dataSender); Assert.AreEqual(expectedUserAgentValue, userAgentValueAfter); }