[CoreWCF.Tests] Gracefully shutdown server

Author: Kielek

test/IntegrationTests/WcfTestsBase.cs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 using System.Net.Sockets;
+using System.Runtime.InteropServices;
 using IntegrationTests.Helpers;
 using Xunit.Abstractions;
 using static OpenTelemetry.Proto.Trace.V1.Span.Types;
@@ -45,7 +46,11 @@ protected virtual void Dispose(bool disposing)
                 }
                 else
                 {
-                    _serverProcess.Process.Kill();
+                    if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || !SendSigTerm(_serverProcess.Process.Id))
+                    {
+                        _serverProcess.Process.Kill();
+                    }
+
                     _serverProcess.Process.WaitForExit();
                 }
 
@@ -122,4 +127,26 @@ private async Task WaitForServer()
 
         Assert.Fail("WCF Server did not open the port.");
     }
+
+    [DllImport("libc", SetLastError = true)]
+#pragma warning disable CA5392 // Use DefaultDllImportSearchPaths attribute for P/Invokes
+#pragma warning disable SA1204 // Static elements should appear before instance elements
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+    private static extern int kill(int pid, int sig);
+#pragma warning restore SA1300 // Element should begin with upper-case letter
+#pragma warning restore SA1204 // Static elements should appear before instance elements
+#pragma warning restore CA5392 // Use DefaultDllImportSearchPaths attribute for P/Invokes
+
+    private static bool SendSigTerm(int processId)
+    {
+        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        {
+            const int sigTerm = 15;
+            var result = kill(processId, sigTerm);
+
+            return result == 0;
+        }
+
+        return false;
+    }
 }

test/test-applications/integrations/TestApplication.Wcf.Core/Program.cs

@@ -26,7 +26,7 @@
 // Configure NetTcp transport
 builder.WebHost.UseNetTcp(9090);
 
-var app = builder.Build();
+using var app = builder.Build();
 
 // Configure CoreWCF
 app.UseServiceModel(serviceBuilder =>