[Fixes #29348][Mvc] Stop the host first and then dispose it! (#29404)

Stop the host before disposing the WebApplicationFactory.

Author: ShreyasJejurkar

src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs

@@ -523,6 +523,7 @@ protected virtual void Dispose(bool disposing)
                 }
 
                 _server?.Dispose();
+                _host?.StopAsync().Wait();
                 _host?.Dispose();
             }
 

src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET  Foundation. All rights reserved.
+// Copyright (c) .NET  Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Collections.Generic;
@@ -65,6 +65,21 @@ public void TestingInfrastructure_GenericHost_WithWithHostBuilderHasServices()
             Assert.NotNull(factory.Services.GetService(typeof(IConfiguration)));
         }
 
+        [Fact]
+        public void TestingInfrastructure_GenericHost_HostShouldStopBeforeDispose()
+        {
+            // Act
+            using var factory = new CustomizedFactory<GenericHostWebSite.Startup>();
+            var callbackCalled = false;
+
+            var lifetimeService = (IHostApplicationLifetime) factory.Services.GetService(typeof(IHostApplicationLifetime));
+            lifetimeService.ApplicationStopped.Register(() => { callbackCalled = true; });
+            factory.Dispose();
+
+            // Assert
+            Assert.True(callbackCalled);
+        }
+
         private class CustomizedFactory<TEntryPoint> : WebApplicationFactory<TEntryPoint> where TEntryPoint : class
         {
             public bool GetTestAssembliesCalled { get; private set; }
@@ -73,6 +88,7 @@ private class CustomizedFactory<TEntryPoint> : WebApplicationFactory<TEntryPoint
             public bool CreateServerCalled { get; private set; }
             public bool CreateHostCalled { get; private set; }
             public IList<string> ConfigureWebHostCalled { get; private set; } = new List<string>();
+            public bool DisposeHostCalled { get; private set; }
 
             protected override void ConfigureWebHost(IWebHostBuilder builder)
             {