Isolate optional desktop shortcut failures

tests/BizTalkPlatformManagementTool.Tests/Program.cs

@@ -50,6 +50,7 @@ namespace BizTalkPlatformManagementTool.Tests
             Run("InstallerDiagnosticLogContainsContextAndExceptionChain", InstallerDiagnosticLogContainsContextAndExceptionChain);
             Run("InstallerDiagnosticLogFallsBackToTemp", InstallerDiagnosticLogFallsBackToTemp);
             Run("InstallerSurvivesUiReportFailure", InstallerSurvivesUiReportFailure);
+            Run("OptionalWindowsIntegrationFailuresAreNonFatal", OptionalWindowsIntegrationFailuresAreNonFatal);
             Console.WriteLine(failures == 0 ? "ALL TESTS PASSED" : failures + " TEST(S) FAILED");
             return failures == 0 ? 0 : 1;
         }
@@ -618,6 +619,56 @@ namespace BizTalkPlatformManagementTool.Tests
             });
         }
 
+        /// <summary>Prüft, dass optionale Desktop- und Warnungsfehler niemals eine Kernoperation abbrechen.</summary>
+        private static void OptionalWindowsIntegrationFailuresAreNonFatal()
+        {
+            InTemp(directory =>
+            {
+                var log = SetupOperationLog.Create(directory, "optional-integration-test");
+                var warnings = new List<string>();
+                var failed = InstallerEngine.TryOptionalWindowsIntegrationStep(
+                    "desktop_shortcut_create",
+                    "Desktop-Verknuepfung erstellen",
+                    Path.Combine(directory, "Public Desktop", "Tool.lnk"),
+                    () => { throw new UnauthorizedAccessException("simulated public desktop ACL denial"); },
+                    log,
+                    warnings.Add);
+                Assert(!failed, "optional ACL failure was reported as success");
+                Assert(warnings.Count == 1 && warnings[0].Contains("Kernoperation wird fortgesetzt"), "operator continuation warning missing");
+
+                var warningFailureEscaped = false;
+                try
+                {
+                    InstallerEngine.TryOptionalWindowsIntegrationStep(
+                        "desktop_shortcut_validate",
+                        "Desktop-Verknuepfung validieren",
+                        Path.Combine(directory, "Public Desktop", "Tool.lnk"),
+                        () => { throw new InvalidOperationException("simulated state mismatch"); },
+                        log,
+                        message => { throw new InvalidOperationException("simulated warning sink failure"); });
+                }
+                catch
+                {
+                    warningFailureEscaped = true;
+                }
+                Assert(!warningFailureEscaped, "optional warning sink failure escaped the isolation boundary");
+
+                var succeeded = InstallerEngine.TryOptionalWindowsIntegrationStep(
+                    "desktop_shortcut_remove",
+                    "Desktop-Verknuepfung entfernen",
+                    Path.Combine(directory, "Public Desktop", "Tool.lnk"),
+                    () => { },
+                    log,
+                    warnings.Add);
+                Assert(succeeded, "successful optional operation was reported as failure");
+
+                var content = File.ReadAllText(log.FilePath);
+                Assert(content.Contains("event=optional_windows_integration_warning role=desktop_shortcut_create"), "optional ACL failure missing from diagnostics");
+                Assert(content.Contains("event=optional_windows_integration_report_failed role=desktop_shortcut_validate"), "warning sink failure missing from diagnostics");
+                Assert(content.Contains("event=optional_windows_integration_completed role=desktop_shortcut_remove"), "optional success missing from diagnostics");
+            });
+        }
+
         /// <summary>Prüft den Diagnose-Log-Fallback bei einem nicht verwendbaren ProgramData-Pfad.</summary>
         private static void InstallerDiagnosticLogFallsBackToTemp()
         {