title: How to write unit test for azure function (Httptrigger) with ILogger
body: <p>Want to write unit test for HttpTrigger GET.
  Have method signature as follow:</p>
  
  <pre><code>public static async Task&lt;HttpResponseMessage&gt; Run(
      [HttpTrigger(AuthorizationLevel.Function, "get", Route = null)]
      HttpRequestMessage request, 
      ILogger log)
  </code></pre>
  
  <p>here, <code>ILogger</code> is type of Microsoft.Extensions.Logging.</p>
  
  <p>How to write unit test case with this injection,
  Tried to create stub of <code>ILogger</code> using below stuff but this needs <code>LoggerFactory</code>.</p>
  
  <pre><code>public class LoggerWriter : Microsoft.Extensions.Logging.Logger&lt;ILogger&gt;
  {
      public LoggerWriter() : base() // this needs logger factory.
      {
      }
  }
  </code></pre>
  
  <p>Any sample unit test for httptrigger azure function to overcome above issue (<code>Ilogger</code> injection) is helpful.</p>