Fix changelog and minor changes for comments

Author: taiwu

src/ResourceManager/AnalysisServices/ChangeLog.md

@@ -18,10 +18,10 @@
         - Additional information about change #1
 -->
 ## Current Release
+* Enable Gateway assocaite/disassociate operations on AS.
 
 ## Version 0.6.7
 * Set minimum dependency of module to PowerShell 5.0
-* Enable Gateway assocaite/disassociate operations on AS.
 
 ## Version 0.6.6
 * Updated to the latest version of the Azure ClientRuntime

src/ResourceManager/AnalysisServices/Commands.AnalysisServices.Test/ScenarioTests/AsTests.ps1

@@ -615,7 +615,11 @@ function Test-AnalysisServicesServerLoginWithSPN
 
 <#
 .SYNOPSIS
-Tests Analysis Services server lifecycle  Failure scenarios (Create, Update, Get, Delete).
+Tests Analysis Services server gateway scenarios (associate/dissociate).
+The assocaited gateway is a unified gateway, which required pre-setup.
+1. Install on-premise gateway on target host https://www.microsoft.com/en-us/download/details.aspx?id=53127 
+2. Follow installation instruction to create azure on-premise gateway resource associating to the host.
+Afterward, use the gateway resource to associate with the AAS for testing.
 #>
 function Test-AnalysisServicesServerGateway
 {

src/ResourceManager/AnalysisServices/Commands.AnalysisServices/Commands/SetAzureRmAnalysisServicesServer.cs

@@ -160,7 +160,7 @@ public override void ExecuteCmdlet()
 
                 if (DisassociateGateway.IsPresent)
                 {
-                    GatewayResourceId = "-";
+                    GatewayResourceId = AnalysisServicesClient.DissasociateGateway;
                 }
 
                 AnalysisServicesServer updatedServer = AnalysisServicesClient.CreateOrUpdateServer(ResourceGroupName, Name, location, Sku, Tag, Administrator, currentServer, BackupBlobContainerUri, ReadonlyReplicaCount, DefaultConnectionMode, setting, GatewayResourceId);

src/ResourceManager/AnalysisServices/Commands.AnalysisServices/Models/AnalysisServicesClient.cs

@@ -33,6 +33,7 @@ public class AnalysisServicesClient
         private readonly AnalysisServicesManagementClient _client;
         private readonly Guid _subscriptionId;
         private readonly string _currentUser;
+        public const string DissasociateGateway = "-";
 
         public AnalysisServicesClient(IAzureContext context)
         {
@@ -89,7 +90,7 @@ public AnalysisServicesServer CreateOrUpdateServer(
             }
 
             GatewayDetails gatewayDetails = null;
-            if (gatewayResourceId == "-")
+            if (gatewayResourceId == DissasociateGateway)
             {
                 gatewayDetails = new GatewayDetails();
             }