[Resources] Small fix to Test-AzResourceGroupDeployment (Azure#27989)

Author: a0x1ab

src/Resources/ResourceManager/Implementation/CmdletBase/TestDeploymentCmdletBase.cs

@@ -35,7 +35,11 @@ public override object GetDynamicParameters()
 
         public void WriteOutput(TemplateValidationInfo validationInfo)
         {
-            if (validationInfo.Errors.Count == 0 && !SuppressDiagnostics.IsPresent)
+            if (validationInfo.Errors.Count > 0)
+            {
+                WriteObject(validationInfo.Errors.Select(e => e.ToPSResourceManagerError()).ToList());
+            }
+            else if (!SuppressDiagnostics.IsPresent && validationInfo.Diagnostics.Count > 0)
             {
                 var builder = new ColoredStringBuilder();
 
@@ -45,10 +49,6 @@ public void WriteOutput(TemplateValidationInfo validationInfo)
 
                 WriteWarning(builder.ToString());
             }
-            else
-            {
-                WriteObject(validationInfo.Errors.Select(e => e.ToPSResourceManagerError()).ToList());
-            }
         }
 
     }

src/Resources/Resources.Test/ResourceGroupDeployments/TestAzureResourceGroupDeploymentCommandTests.cs

@@ -195,7 +195,8 @@ public void ValidatesPSResourceGroupDeploymentWithUserTemplateWithDiagnosticsSup
             PSObject expectedObject = new PSObject(JTokenExtensions.ConvertPropertyValueForPsObject(propertyValue: expectedToken));
 
             commandRuntimeMock.Verify(f => f.WriteObject(expectedObject, true), Times.Never());
-            commandRuntimeMock.Verify(f => f.WriteObject(new List<PSResourceManagerError>()), Times.Once());
+            commandRuntimeMock.Verify(f => f.WriteWarning(It.IsAny<string>()), Times.Never());
+            commandRuntimeMock.Verify(f => f.WriteObject(It.IsAny<List<PSResourceManagerError>>()), Times.Never());
         }
 
         [Fact]
@@ -228,5 +229,34 @@ public void ValidatesPSResourceGroupDeploymentWithUserTemplateProviderNoRbac()
 
             Assert.NotNull(actualParameters.TemplateParameterObject);
         }
+
+        [Fact]
+        [Trait(Category.AcceptanceType, Category.CheckIn)]
+        public void ValidatesPSResourceGroupDeploymentWithUserTemplateNoDiagnosticsNoErrors()
+        {
+            PSDeploymentCmdletParameters expectedParameters = new PSDeploymentCmdletParameters()
+            {
+                TemplateFile = templateFile
+            };
+            PSDeploymentCmdletParameters actualParameters = new PSDeploymentCmdletParameters();
+
+            TemplateValidationInfo expectedResults = new(new DeploymentValidateResult());
+
+            resourcesClientMock.Setup(f => f.ValidateDeployment(
+                It.IsAny<PSDeploymentCmdletParameters>()))
+                .Returns(expectedResults)
+                .Callback((PSDeploymentCmdletParameters p) => { actualParameters = p; });
+
+            cmdlet.ResourceGroupName = resourceGroupName;
+            cmdlet.TemplateFile = expectedParameters.TemplateFile;
+
+            cmdlet.ExecuteCmdlet();
+
+            Assert.Equal(expectedParameters.TemplateFile, actualParameters.TemplateFile);
+            Assert.NotNull(actualParameters.TemplateParameterObject);
+
+            commandRuntimeMock.Verify(f => f.WriteWarning(It.IsAny<string>()), Times.Never());
+            commandRuntimeMock.Verify(f => f.WriteObject(It.IsAny<List<PSResourceManagerError>>()), Times.Never());
+        }
     }
 }

src/Resources/Resources/ChangeLog.md

@@ -19,6 +19,7 @@
 -->
 
 ## Upcoming Release
+* Fixed empty warning output issue for cmdlet `Test-AzResourceGroupDeployment` [#27888]
 
 ## Version 8.0.0
 * [Breaking Change] Updated API version of resource types from latest to DefaultApiVersion for cmdlets `*-AzResource` and `Invoke-AzResourceAction`.