fix(migration): Expand Get-DbaCmObject unit tests per review

- Added WMI error helper tests (GetWmiErrorReason, GetWmiErrorCategory, IsProviderLoadFailure)
- Changed WMI helpers from private to internal for testability
- Added query parsing edge cases (case-insensitive, no FROM, null)
- Added additional CimErrorMessage and FindCimException edge cases
- Total: 34 unit tests (up from 16)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: potatoqualitee

project/dbatools.Tests/Commands/GetDbaCmObjectCommandTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Management.Automation;
 using Microsoft.Management.Infrastructure;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -42,17 +43,49 @@ public void ResolveCimError_NullClassName_DoesNotThrow()
         [TestMethod]
         public void ResolveCimError_QueryExtractsClassName()
         {
-            // Arrange - query with FROM clause
+            // Arrange - query with FROM clause; the extracted class replaces the original ClassName
             var ex = new Exception("Some error");
             string query = "SELECT Name, State FROM Win32_Service WHERE StartMode='Auto'";
 
             // Act
             var result = Dbatools.Commands.GetDbaCmObjectCommand.ResolveCimError(
                 ex, "server01", "OriginalClass", @"root\cimv2", query);
 
-            // Assert - the message should reference the extracted class name from the query
+            // Assert - since this is an unknown code (no CimException), message uses default format
+            // but the className should have been replaced with Win32_Service from query parsing
+            Assert.IsNotNull(result.Message);
+            Assert.IsTrue(result.BadConnection, "Unknown code should flag bad connection");
+        }
+
+        [TestMethod]
+        public void ResolveCimError_QueryCaseInsensitive_ExtractsClassName()
+        {
+            // Arrange - lowercase "from" should still be matched
+            var ex = new Exception("Some error");
+            string query = "select * from Win32_Process where Name='test'";
+
+            // Act
+            var result = Dbatools.Commands.GetDbaCmObjectCommand.ResolveCimError(
+                ex, "server01", "OriginalClass", @"root\cimv2", query);
+
+            // Assert
+            Assert.IsNotNull(result.Message);
+        }
+
+        [TestMethod]
+        public void ResolveCimError_QueryNoFromClause_KeepsOriginalClassName()
+        {
+            // Arrange - malformed query without FROM
+            var ex = new Exception("Some error");
+            string query = "INVALID QUERY TEXT";
+
+            // Act
+            var result = Dbatools.Commands.GetDbaCmObjectCommand.ResolveCimError(
+                ex, "server01", "Win32_OS", @"root\cimv2", query);
+
+            // Assert - should still produce valid output without crashing
+            Assert.IsNotNull(result);
             Assert.IsNotNull(result.Message);
-            // The class name should be extracted from the query, not the original ClassName
         }
 
         [TestMethod]
@@ -69,6 +102,21 @@ public void ResolveCimError_EmptyQuery_UsesClassName()
             Assert.IsNotNull(result.Message);
         }
 
+        [TestMethod]
+        public void ResolveCimError_NullQuery_UsesClassName()
+        {
+            // Arrange
+            var ex = new Exception("Some error");
+
+            // Act
+            var result = Dbatools.Commands.GetDbaCmObjectCommand.ResolveCimError(
+                ex, "server01", "Win32_Process", @"root\cimv2", null);
+
+            // Assert
+            Assert.IsNotNull(result.Message);
+            Assert.IsTrue(result.BadConnection);
+        }
+
         #endregion
 
         #region GetCimErrorMessage
@@ -156,6 +204,41 @@ public void GetCimErrorMessage_AllCodes_ContainComputerName()
             }
         }
 
+        [TestMethod]
+        public void GetCimErrorMessage_Code6_ContainsObjectNotFound()
+        {
+            // Act
+            string message = Dbatools.Commands.GetDbaCmObjectCommand.GetCimErrorMessage(
+                6, "server01", "Win32_Widget", @"root\cimv2");
+
+            // Assert
+            Assert.IsTrue(message.Contains("could not be found"), "Code 6 should indicate object not found");
+            Assert.IsTrue(message.Contains("Win32_Widget"), "Message should reference the class name");
+        }
+
+        [TestMethod]
+        public void GetCimErrorMessage_Code20_ContainsNamespaceNotEmpty()
+        {
+            // Act
+            string message = Dbatools.Commands.GetDbaCmObjectCommand.GetCimErrorMessage(
+                20, "server01", "SomeClass", @"root\test");
+
+            // Assert
+            Assert.IsTrue(message.Contains("not empty"), "Code 20 should indicate namespace not empty");
+            Assert.IsTrue(message.Contains(@"root\test"), "Message should reference the namespace");
+        }
+
+        [TestMethod]
+        public void GetCimErrorMessage_NegativeCode_ReturnsDefaultMessage()
+        {
+            // Act
+            string message = Dbatools.Commands.GetDbaCmObjectCommand.GetCimErrorMessage(
+                -1, "server01", "Win32_OS", @"root\cimv2");
+
+            // Assert
+            Assert.IsTrue(message.Contains("unexpected error"), "Negative code should return default message");
+        }
+
         #endregion
 
         #region FindCimException
@@ -197,6 +280,166 @@ public void FindCimException_NestedNonCimExceptions_ReturnsNull()
             Assert.IsNull(result, "Should return null when no CimException in chain");
         }
 
+        [TestMethod]
+        public void FindCimException_DeeplyNestedNonCim_ReturnsNull()
+        {
+            // Arrange - three levels deep, still no CimException
+            var level1 = new ArgumentException("level 1");
+            var level2 = new InvalidOperationException("level 2", level1);
+            var level3 = new Exception("level 3", level2);
+
+            // Act
+            var result = Dbatools.Commands.GetDbaCmObjectCommand.FindCimException(level3);
+
+            // Assert
+            Assert.IsNull(result, "Should return null with deeply nested non-CIM exceptions");
+        }
+
+        #endregion
+
+        #region GetWmiErrorReason
+
+        [TestMethod]
+        public void GetWmiErrorReason_UnauthorizedAccessException_ReturnsCorrectReason()
+        {
+            // Arrange
+            var ex = new UnauthorizedAccessException("Access denied");
+
+            // Act
+            string result = Dbatools.Commands.GetDbaCmObjectCommand.GetWmiErrorReason(ex);
+
+            // Assert
+            Assert.AreEqual("UnauthorizedAccessException", result);
+        }
+
+        [TestMethod]
+        public void GetWmiErrorReason_InnerUnauthorizedAccess_ReturnsCorrectReason()
+        {
+            // Arrange
+            var inner = new UnauthorizedAccessException("Access denied");
+            var outer = new Exception("Wrapper", inner);
+
+            // Act
+            string result = Dbatools.Commands.GetDbaCmObjectCommand.GetWmiErrorReason(outer);
+
+            // Assert
+            Assert.AreEqual("UnauthorizedAccessException", result);
+        }
+
+        [TestMethod]
+        public void GetWmiErrorReason_GenericException_ReturnsNull()
+        {
+            // Arrange
+            var ex = new Exception("Some generic error");
+
+            // Act
+            string result = Dbatools.Commands.GetDbaCmObjectCommand.GetWmiErrorReason(ex);
+
+            // Assert
+            Assert.IsNull(result, "Generic exceptions should return null reason");
+        }
+
+        [TestMethod]
+        public void GetWmiErrorReason_NullInnerException_ReturnsNull()
+        {
+            // Arrange
+            var ex = new InvalidOperationException("No inner exception");
+
+            // Act
+            string result = Dbatools.Commands.GetDbaCmObjectCommand.GetWmiErrorReason(ex);
+
+            // Assert
+            Assert.IsNull(result, "Exception without inner UnauthorizedAccessException should return null");
+        }
+
+        #endregion
+
+        #region GetWmiErrorCategory
+
+        [TestMethod]
+        public void GetWmiErrorCategory_GenericException_ReturnsNull()
+        {
+            // Arrange
+            var ex = new Exception("Not a RuntimeException");
+
+            // Act
+            string result = Dbatools.Commands.GetDbaCmObjectCommand.GetWmiErrorCategory(ex);
+
+            // Assert
+            Assert.IsNull(result, "Non-RuntimeException should return null category");
+        }
+
+        [TestMethod]
+        public void GetWmiErrorCategory_NullException_DoesNotThrow()
+        {
+            // Arrange
+            var ex = new InvalidOperationException("test");
+
+            // Act
+            string result = Dbatools.Commands.GetDbaCmObjectCommand.GetWmiErrorCategory(ex);
+
+            // Assert
+            Assert.IsNull(result);
+        }
+
+        #endregion
+
+        #region IsProviderLoadFailure
+
+        [TestMethod]
+        public void IsProviderLoadFailure_MessageContainsKeyword_ReturnsTrue()
+        {
+            // Arrange
+            var ex = new Exception("Error: ProviderLoadFailure occurred");
+
+            // Act
+            bool result = Dbatools.Commands.GetDbaCmObjectCommand.IsProviderLoadFailure(ex);
+
+            // Assert
+            Assert.IsTrue(result, "Should detect ProviderLoadFailure in exception message");
+        }
+
+        [TestMethod]
+        public void IsProviderLoadFailure_InnerExceptionContainsKeyword_ReturnsTrue()
+        {
+            // Arrange
+            var inner = new Exception("ProviderLoadFailure in WMI subsystem");
+            var outer = new Exception("Outer error", inner);
+
+            // Act
+            bool result = Dbatools.Commands.GetDbaCmObjectCommand.IsProviderLoadFailure(outer);
+
+            // Assert
+            Assert.IsTrue(result, "Should detect ProviderLoadFailure in inner exception message");
+        }
+
+        [TestMethod]
+        public void IsProviderLoadFailure_NoKeyword_ReturnsFalse()
+        {
+            // Arrange
+            var ex = new Exception("Some other WMI error");
+
+            // Act
+            bool result = Dbatools.Commands.GetDbaCmObjectCommand.IsProviderLoadFailure(ex);
+
+            // Assert
+            Assert.IsFalse(result, "Should return false when ProviderLoadFailure is not in any message");
+        }
+
+        [TestMethod]
+        public void IsProviderLoadFailure_NullMessage_ReturnsFalse()
+        {
+            // Arrange - exception with null message via inner exception chain
+            var inner = new Exception("normal error");
+            var outer = new Exception("also normal", inner);
+
+            // Act
+            bool result = Dbatools.Commands.GetDbaCmObjectCommand.IsProviderLoadFailure(outer);
+
+            // Assert
+            Assert.IsFalse(result);
+        }
+
         #endregion
 
         #region CimErrorInfo
@@ -228,6 +471,20 @@ public void CimErrorInfo_Constructor_BadCredentials()
             Assert.IsTrue(info.BadCredentials);
         }
 
+        [TestMethod]
+        public void CimErrorInfo_Constructor_NullMessage()
+        {
+            // Act
+            var info = new Dbatools.Commands.GetDbaCmObjectCommand.CimErrorInfo(
+                0, null, false, false);
+
+            // Assert
+            Assert.AreEqual(0, info.ErrorCode);
+            Assert.IsNull(info.Message);
+            Assert.IsFalse(info.BadConnection);
+            Assert.IsFalse(info.BadCredentials);
+        }
+
         #endregion
     }
 }

project/dbatools/Commands/GetDbaCmObjectCommand.cs

@@ -718,7 +718,7 @@ internal static CimException FindCimException(Exception ex)
         /// <summary>
         /// Gets the reason string from a WMI error (checking CategoryInfo.Reason equivalent).
         /// </summary>
-        private static string GetWmiErrorReason(Exception ex)
+        internal static string GetWmiErrorReason(Exception ex)
         {
             if (ex is RuntimeException runtimeEx && runtimeEx.ErrorRecord != null)
             {
@@ -735,7 +735,7 @@ private static string GetWmiErrorReason(Exception ex)
         /// <summary>
         /// Gets the error category string from a WMI error.
         /// </summary>
-        private static string GetWmiErrorCategory(Exception ex)
+        internal static string GetWmiErrorCategory(Exception ex)
         {
             if (ex is RuntimeException runtimeEx && runtimeEx.ErrorRecord != null)
             {
@@ -748,7 +748,7 @@ private static string GetWmiErrorCategory(Exception ex)
         /// <summary>
         /// Checks if the WMI error is a ProviderLoadFailure.
         /// </summary>
-        private static bool IsProviderLoadFailure(Exception ex)
+        internal static bool IsProviderLoadFailure(Exception ex)
         {
             // Check for ProviderLoadFailure in the exception message or error code
             if (ex.Message != null && ex.Message.Contains("ProviderLoadFailure"))