incorporated review comments.

Author: Kalyan-microsoft

src/Agent.Listener/Configuration/ConfigurationManager.cs

@@ -2,10 +2,10 @@
 using Microsoft.VisualStudio.Services.Agent.Util;
 using Microsoft.VisualStudio.Services.Client;
 using Microsoft.VisualStudio.Services.Common;
-using Microsoft.VisualStudio.Services.WebApi;
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -223,7 +223,7 @@ public async Task ConfigureAsync(Dictionary<string, string> args, HashSet<string
                 agentName = consoleWizard.ReadValue(CliArgs.Agent,
                                                 StringUtil.Loc("AgentName"),
                                                 false,
-                                                Environment.MachineName,
+                                                Environment.MachineName ?? "myagent",
                                                 // can do better
                                                 Validators.NonEmptyValidator,
                                                 args,

src/Test/L0/Listener/AgentL0.cs

@@ -190,12 +190,12 @@ public async void TestRunAsync()
         [Trait("Category", "Agent")]
         public async void TestExecuteCommandForRunAsService(string[] args, bool configureAsService, Times expectedTimes)
         {
-            using (var thc = new TestHostContext(this))
+            using (var hc = new TestHostContext(this))
             {
-                thc.SetSingleton<IConfigurationManager>(_configurationManager.Object);
-                thc.SetSingleton<IMessageListener>(_messageListener.Object);
+                hc.SetSingleton<IConfigurationManager>(_configurationManager.Object);
+                hc.SetSingleton<IMessageListener>(_messageListener.Object);
 
-                CommandLineParser clp = new CommandLineParser(thc);
+                CommandLineParser clp = new CommandLineParser(hc);
                 clp.Parse(args);
 
                 _configurationManager.Setup(x => x.IsConfigured()).Returns(true);
@@ -205,7 +205,7 @@ public async void TestExecuteCommandForRunAsService(string[] args, bool configur
                     .Returns(Task.FromResult(false));
 
                 var agent = new Agent.Listener.Agent();
-                agent.Initialize(thc);
+                agent.Initialize(hc);
                 agent.TokenSource = new CancellationTokenSource();
                 await agent.ExecuteCommand(clp);