If you right click WebService1.asmx and run in browser I get this Test method call and if I Invoke I get an error.

I have added in web config file it is working now.

<add name="*.asmx_*" path="*.asmx" verb="*" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"preCondition="integratedMode,runtimeVersionv4.0" />