Quarantining tests (#20631)

* Quarantining tests

* Namespace collision

src/ProjectTemplates/test/AssemblyInfo.AssemblyFixtures.cs

@@ -2,10 +2,13 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Microsoft.AspNetCore.E2ETesting;
+using Microsoft.AspNetCore.Testing;
 using Templates.Test.Helpers;
 using Xunit;
 
 [assembly: TestFramework("Microsoft.AspNetCore.E2ETesting.XunitTestFrameworkWithAssemblyFixture", "ProjectTemplates.Tests")]
 
-[assembly: AssemblyFixture(typeof(ProjectFactoryFixture))]
+[assembly: Microsoft.AspNetCore.E2ETesting.AssemblyFixture(typeof(ProjectFactoryFixture))]
-[assembly: AssemblyFixture(typeof(SeleniumStandaloneServer))]
+[assembly: Microsoft.AspNetCore.E2ETesting.AssemblyFixture(typeof(SeleniumStandaloneServer))]
+
+[assembly: QuarantinedTest("Investigation pending in https://github.com/dotnet/aspnetcore/issues/20479")]

src/Security/Authentication/test/SecureDataFormatTests.cs

@@ -49,6 +49,7 @@ namespace Microsoft.AspNetCore.Authentication.DataHandler
         }
 
         [Fact]
+        [QuarantinedTest]
         public void UnprotectWithDifferentPurposeFails()
         {
             var provider = ServiceProvider.GetRequiredService<IDataProtectionProvider>();

src/Servers/Kestrel/test/Interop.FunctionalTests/HttpClientHttp2InteropTests.cs

@@ -1415,6 +1415,7 @@ namespace Interop.FunctionalTests
         // Settings_InitialWindowSize_Lower_Client - Not configurable.
 
         [Theory]
+        [QuarantinedTest]
         [MemberData(nameof(SupportedSchemes))]
         public async Task Settings_InitialWindowSize_Server(string scheme)
         {

src/Tools/Microsoft.dotnet-openapi/test/OpenApiAddURLTests.cs

@@ -420,6 +420,7 @@ namespace Microsoft.DotNet.OpenApi.Add.Tests
         }
 
         [Fact]
+        [QuarantinedTest]
         public async Task OpenAPi_Add_URL_InvalidUrl()
         {
             var project = CreateBasicProject(withOpenApi: false);

src/Tools/dotnet-watch/test/MsBuildFileSetFactoryTest.cs

@@ -77,6 +77,7 @@ namespace Microsoft.DotNet.Watcher.Tools.Tests
         }
 
         [Fact]
+        [QuarantinedTest]
         public async Task SingleTfm()
         {
             _tempDir