Use authenticate endpoint for testing runner connection. (#311)

* use authenticate endpoint for testing runner connection.

* PR feedback.

Author: TingluoHuang

src/Runner.Listener/Configuration/ConfigurationManager.cs

@@ -277,12 +277,15 @@ public async Task ConfigureAsync(CommandSettings command)
                 throw new NotSupportedException("Message queue listen OAuth token.");
             }
 
-            // Testing agent connection, detect any protential connection issue, like local clock skew that cause OAuth token expired.
+            // Testing agent connection, detect any potential connection issue, like local clock skew that cause OAuth token expired.
             var credMgr = HostContext.GetService<ICredentialManager>();
             VssCredentials credential = credMgr.LoadCredentials();
             try
             {
                 await _runnerServer.ConnectAsync(new Uri(runnerSettings.ServerUrl), credential);
+                // ConnectAsync() hits _apis/connectionData which is an anonymous endpoint
+                // Need to hit an authenticate endpoint to trigger OAuth token exchange.
+                await _runnerServer.GetAgentPoolsAsync();
                 _term.WriteSuccessMessage("Runner connection is good");
             }
             catch (VssOAuthTokenRequestException ex) when (ex.Message.Contains("Current server time is"))

src/Test/L0/Listener/Configuration/ConfigurationManagerL0.cs

@@ -175,8 +175,8 @@ public async Task CanEnsureConfigure()
                 Assert.True(s.PoolId.Equals(_expectedPoolId));
                 Assert.True(s.WorkFolder.Equals(_expectedWorkFolder));
 
-                // validate GetAgentPoolsAsync gets called once with automation pool type
-                _runnerServer.Verify(x => x.GetAgentPoolsAsync(It.IsAny<string>(), It.Is<TaskAgentPoolType>(p => p == TaskAgentPoolType.Automation)), Times.Once);
+                // validate GetAgentPoolsAsync gets called twice with automation pool type
+                _runnerServer.Verify(x => x.GetAgentPoolsAsync(It.IsAny<string>(), It.Is<TaskAgentPoolType>(p => p == TaskAgentPoolType.Automation)), Times.Exactly(2));
 
                 _runnerServer.Verify(x => x.AddAgentAsync(It.IsAny<int>(), It.Is<TaskAgent>(a => a.Labels.Contains("self-hosted") && a.Labels.Contains(VarUtil.OS) && a.Labels.Contains(VarUtil.OSArchitecture))), Times.Once);
             }