Updated as per design review

Author: anusapan

src/IotHub/IotHub.Test/ScenarioTests/IotHubDPDeviceTests.ps1

@@ -67,25 +67,25 @@ function Test-AzureRmIotHubDeviceLifecycle
 	$device1twin = Get-AzIotHubDeviceTwin -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName -DeviceId $device1
 	Assert-True { $device1twin.DeviceId -eq $device1}
 
-	# Update device twin
+	# Partial update device twin
 	$tags1 = @{}
 	$tags1.Add('Test1', '1')
-	$updateddevice1twin1 = Update-AzIotHubDeviceTwin -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName -DeviceId $device1 -tag $tags1
+	$updateddevice1twin1 = Update-AzIotHubDeviceTwin -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName -DeviceId $device1 -tag $tags1 -Partial
 	Assert-True { $updateddevice1twin1.DeviceId -eq $device1}
 	Assert-True { $updateddevice1twin1.tags.Count -eq 1}
 
 	$tags2 = @{}
 	$tags2.Add('Test2', '2')
-	$updateddevice1twin2 = Update-AzIotHubDeviceTwin -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName -DeviceId $device1 -tag $tags2
+	$updateddevice1twin2 = Update-AzIotHubDeviceTwin -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName -DeviceId $device1 -tag $tags2 -Partial
 	Assert-True { $updateddevice1twin2.DeviceId -eq $device1}
 	Assert-True { $updateddevice1twin2.tags.Count -eq 2}
 
-	# Set device twin
+	# Update device twin
 	$tags3 = @{}
 	$tags3.Add('Test3', '3')
-	$setdevice1twin = Set-AzIotHubDeviceTwin -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName -DeviceId $device1 -tag $tags3
-	Assert-True { $setdevice1twin.DeviceId -eq $device1}
-	Assert-True { $setdevice1twin.tags.Count -eq 1}
+	$updateddevice1twin3 = Update-AzIotHubDeviceTwin -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName -DeviceId $device1 -tag $tags3
+	Assert-True { $updateddevice1twin3.DeviceId -eq $device1}
+	Assert-True { $updateddevice1twin3.tags.Count -eq 1}
 
 	# Get all devices
 	$devices = Get-AzIotHubDevice -ResourceGroupName $ResourceGroupName -IotHubName $IotHubName

src/IotHub/IotHub.Test/SessionRecords/Microsoft.Azure.Commands.IotHub.Test.ScenarioTests.IotHubDPDeviceTests/TestAzureIotHubDeviceLifecycle.json

@@ -101,7 +101,7 @@ CmdletsToExport = 'Add-AzIotHubKey', 'Get-AzIotHubEventHubConsumerGroup',
                'Set-AzIotHubDeviceParent', 'Add-AzIotHubDeviceChildren', 
                'Remove-AzIotHubDeviceChildren', 'Get-AzIotHubDeviceChildren',
                'Get-AzIotHubDistributedTracing', 'Set-AzIotHubDistributedTracing',
-               'Get-AzIotHubDeviceTwin', 'Update-AzIotHubDeviceTwin', 'Set-AzIotHubDeviceTwin'
+               'Get-AzIotHubDeviceTwin', 'Update-AzIotHubDeviceTwin'
 # Variables to export from this module
 # VariablesToExport = @()
 

src/IotHub/IotHub/Az.IotHub.psd1

@@ -24,7 +24,6 @@
 * Manage IoT device twin configuration, New cmdlets are:
     - `Get-AzIotHubDeviceTwin`
     - `Update-AzIotHubDeviceTwin`
-    - `Set-AzIotHubDeviceTwin`
 
 ## Version 2.2.0
 * Added support to manage devices in an Iot Hub. New Cmdlets are:

src/IotHub/IotHub/ChangeLog.md

@@ -72,6 +72,9 @@ public class UpdateAzIotHubDeviceTwin : IotHubBaseCmdlet
         [ValidateNotNullOrEmpty]
         public Hashtable Desired { get; set; }
 
+        [Parameter(Mandatory = false, HelpMessage = "Allows to only partially update the tags and desired properties of a device twin.")]
+        public SwitchParameter Partial { get; set; }
+
         public override void ExecuteCmdlet()
         {
             if (ShouldProcess(this.DeviceId, Properties.Resources.UpdateIotHubDeviceTwin))
@@ -116,7 +119,14 @@ public override void ExecuteCmdlet()
                     deviceTwin.Properties.Desired = new TwinCollection(JsonConvert.SerializeObject(this.Desired));
                 }
 
-                this.WriteObject(registryManager.UpdateTwinAsync(this.DeviceId, deviceTwin, deviceTwin.ETag).GetAwaiter().GetResult());
+                if (this.Partial.IsPresent)
+                {
+                    this.WriteObject(registryManager.UpdateTwinAsync(this.DeviceId, deviceTwin, deviceTwin.ETag).GetAwaiter().GetResult());
+                }
+                else
+                {
+                    this.WriteObject(registryManager.ReplaceTwinAsync(this.DeviceId, deviceTwin, deviceTwin.ETag).GetAwaiter().GetResult());
+                }
             }
         }
     }

src/IotHub/IotHub/IotHub/DataPlane/Device/SetAzIotHubDeviceTwin.cs

@@ -219,9 +219,6 @@
   <data name="SetIotHubDistributedTracing" xml:space="preserve">
     <value>Update Distributed Tracing</value>
   </data>
-  <data name="SetIotHubDeviceTwin" xml:space="preserve">
-    <value>Replace Device Twin</value>
-  </data>
   <data name="UpdateIotHubDeviceTwin" xml:space="preserve">
     <value>Update Device Twin</value>
   </data>

src/IotHub/IotHub/IotHub/DataPlane/Device/UpdateAzIotHubDeviceTwin.cs

@@ -155,9 +155,6 @@ Update an IoT Hub device.
 ### [Set-AzIotHubDeviceParent](Set-AzIotHubDeviceParent.md)
 Set the parent device of the specified device.
 
-### [Set-AzIotHubDeviceTwin](Set-AzIotHubDeviceTwin.md)
-Replaces tags and desired properties of a device twin.
-
 ### [Set-AzIotHubDistributedTracing](Set-AzIotHubDistributedTracing.md)
 Update the distributed tracing options for a device.