avoid code duplication for disabling parallelization with xUnit

src/libraries/Common/tests/TestUtilities/System/DisableParallelization.cs

@@ -0,0 +1,12 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Xunit;
+
+namespace System
+{
+    // The collection definitions must be in the same assembly as the test that uses them.
+    // So please use "Compile Include" in the project file to include this class.
+    [CollectionDefinition(nameof(DisableParallelization), DisableParallelization = true)]
+    public class DisableParallelization { }
+}

src/libraries/System.ComponentModel.TypeConverter/tests/MemberDescriptorTests.cs

@@ -9,11 +9,8 @@
 
 namespace System.ComponentModel.Tests
 {
-    [CollectionDefinition("NoParallelTests", DisableParallelization = true)]
-    public partial class NoParallelTests { }
-
     // Mutable static comparision in the implementation
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public class MemberDescriptorTests
     {
         [Theory]

src/libraries/System.ComponentModel.TypeConverter/tests/ReflectionCachesUpdateHandlerTests.cs

@@ -7,7 +7,7 @@
 namespace System.ComponentModel.Tests
 {
     [SimpleUpdateTest]
-    [Collection("NoParallelTests")] // Clears the cache which disrupts concurrent tests
+    [Collection(nameof(DisableParallelization))] // Clears the cache which disrupts concurrent tests
     public class ReflectionCachesUpdateHandlerTests
     {
         [Fact]

src/libraries/System.ComponentModel.TypeConverter/tests/System.ComponentModel.TypeConverter.Tests.csproj

@@ -153,6 +153,8 @@
     <Compile Include="Security\Authentication\ExtendedProtection\ExtendedProtectionPolicyTypeConverterTests.cs" />
     <Compile Include="XTypeDescriptionProviderTests.cs" />
 
+    <Compile Include="$(CommonTestPath)TestUtilities\System\DisableParallelization.cs"
+        Link="Common\TestUtilities\System\DisableParallelization.cs" />
     <TrimmerRootDescriptor Include="$(ILLinkDescriptorsPath)ILLink.Descriptors.Castle.xml" />
   </ItemGroup>
   <ItemGroup>

src/libraries/System.ComponentModel.TypeConverter/tests/TypeDescriptorTests.cs

@@ -10,7 +10,7 @@
 
 namespace System.ComponentModel.Tests
 {
-    [Collection("NoParallelTests")] // manipulates cache
+    [Collection(nameof(DisableParallelization))] // manipulates cache
     public class TypeDescriptorTests
     {
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotMonoAOT))] // Mock will try to JIT 

src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.unit.cs

@@ -1086,7 +1086,7 @@ public void FileSystemWatcher_ModifyFiltersConcurrentWithEvents()
         }
     }
 
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public partial class DangerousFileSystemWatcherTests : FileSystemWatcherTest
     {
         private readonly ITestOutputHelper _output;

src/libraries/System.IO.FileSystem.Watcher/tests/System.IO.FileSystem.Watcher.Tests.csproj

@@ -35,6 +35,8 @@
              Link="Common\System\IO\TempFile.cs" />
     <Compile Include="$(CommonTestPath)System\IO\TempDirectory.cs"
              Link="Common\System\IO\TempDirectory.cs" />
+    <Compile Include="$(CommonTestPath)TestUtilities\System\DisableParallelization.cs"
+             Link="Common\TestUtilities\System\DisableParallelization.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetsLinux)' == 'true' or '$(TargetsOSX)' == 'true' or '$(TargetsiOS)' == 'true' or '$(TargetstvOS)' == 'true'">
     <Compile Include="FileSystemWatcher.Unix.cs" />

src/libraries/System.IO.FileSystem.Watcher/tests/Utility/FileSystemWatcherTest.cs

@@ -11,9 +11,6 @@
 
 namespace System.IO.Tests
 {
-    [CollectionDefinition("NoParallelTests", DisableParallelization = true)]
-    public partial class NoParallelTests { }
-
     public abstract partial class FileSystemWatcherTest : FileCleanupTestBase
     {
         // Events are reported asynchronously by the OS, so allow an amount of time for

src/libraries/System.IO.FileSystem/tests/DisabledFileLockingTests/System.IO.FileSystem.DisabledFileLocking.Tests.csproj

@@ -20,6 +20,7 @@
     <Compile Include="..\PortedCommon\IOInputs.cs" />
     <Compile Include="..\PortedCommon\IOServices.cs" />
     <Compile Include="$(CommonTestPath)System\IO\PathFeatures.cs" Link="Common\System\IO\PathFeatures.cs" />
+    <Compile Include="$(CommonTestPath)TestUtilities\System\DisableParallelization.cs" Link="Common\TestUtilities\System\DisableParallelization.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetsUnix)' == 'true'">
     <Compile Remove="..\**\*.Windows.cs" />

src/libraries/System.IO.FileSystem/tests/FileStream/FileStreamConformanceTests.Windows.cs

@@ -77,7 +77,7 @@ protected override string GetTestFilePath(int? index = null, [CallerMemberName]
     }
 
     [PlatformSpecific(TestPlatforms.Windows)] // the test setup is Windows-specifc
-    [Collection("NoParallelTests")] // don't run in parallel, as file sharing logic is not thread-safe
+    [Collection(nameof(DisableParallelization))] // don't run in parallel, as file sharing logic is not thread-safe
     [OuterLoop("Requires admin privileges to create a file share")]
     [ConditionalClass(typeof(UncFilePathFileStreamStandaloneConformanceTests), nameof(CanShareFiles))]
     public class UncFilePathFileStreamStandaloneConformanceTests : UnbufferedAsyncFileStreamStandaloneConformanceTests

src/libraries/System.IO.FileSystem/tests/FileStream/ctor_options.cs

@@ -10,7 +10,7 @@ namespace System.IO.Tests
     // Don't run in parallel as the WhenDiskIsFullTheErrorMessageContainsAllDetails test
     // consumes entire available free space on the disk (only on Linux, this is how posix_fallocate works)
     // and if we try to run other disk-writing test in the meantime we are going to get "No space left on device" exception.
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public partial class FileStream_ctor_options : FileStream_ctor_str_fm_fa_fs_buffer_fo
     {
         protected override string GetExpectedParamName(string paramName) => "value";
@@ -166,7 +166,4 @@ public void WhenDiskIsFullTheErrorMessageContainsAllDetails(FileMode mode)
             Assert.False(exists);
         }
     }
-
-    [CollectionDefinition("NoParallelTests", DisableParallelization = true)]
-    public partial class NoParallelTests { }
 }

src/libraries/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj

@@ -217,6 +217,7 @@
     <Compile Include="$(CommonTestPath)System\IO\PathFeatures.cs" Link="Common\System\IO\PathFeatures.cs" />
     <Content Include="DirectoryInfo\test-dir\dummy.txt" Link="test-dir\dummy.txt" />
     <Compile Include="$(CommonPath)System\IO\PathInternal.CaseSensitivity.cs" Link="Common\System\IO\PathInternal.CaseSensitivity.cs" />
+    <Compile Include="$(CommonTestPath)TestUtilities\System\DisableParallelization.cs" Link="Common\TestUtilities\System\DisableParallelization.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="$(CommonTestPath)StreamConformanceTests\StreamConformanceTests.csproj" />

src/libraries/System.Net.Http/tests/FunctionalTests/SocketsHttpHandlerTest.Http2FlowControl.cs

@@ -11,16 +11,11 @@
 
 namespace System.Net.Http.Functional.Tests
 {
-    [CollectionDefinition(nameof(NonParallelTestCollection), DisableParallelization = true)]
-    public class NonParallelTestCollection
-    {
-    }
-
     // This test class contains tests which are strongly timing-dependent.
     // There are two mitigations avoid flaky behavior on CI:
     // - Parallel test execution is disabled
     // - Using extreme parameters, and checks which are very unlikely to fail, if the implementation is correct
-    [Collection(nameof(NonParallelTestCollection))]
+    [Collection(nameof(DisableParallelization))]
     [ConditionalClass(typeof(SocketsHttpHandler_Http2FlowControl_Test), nameof(IsSupported))]
     public sealed class SocketsHttpHandler_Http2FlowControl_Test : HttpClientHandlerTestBase
     {

src/libraries/System.Net.Http/tests/FunctionalTests/SocketsHttpHandlerTest.Http2KeepAlivePing.cs

@@ -13,7 +13,7 @@
 
 namespace System.Net.Http.Functional.Tests
 {
-    [Collection(nameof(NonParallelTestCollection))]
+    [Collection(nameof(DisableParallelization))]
     [ConditionalClass(typeof(SocketsHttpHandler_Http2KeepAlivePing_Test), nameof(IsSupported))]
     public sealed class SocketsHttpHandler_Http2KeepAlivePing_Test : HttpClientHandlerTestBase
     {

src/libraries/System.Net.Http/tests/FunctionalTests/SocketsHttpHandlerTest.cs

@@ -3143,23 +3143,23 @@ public SocketsHttpHandler_HttpClientHandler_Cancellation_Test_Http2(ITestOutputH
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMsQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_Http3_MsQuic : HttpClientHandlerTest_Http3
     {
         public SocketsHttpHandlerTest_Http3_MsQuic(ITestOutputHelper output) : base(output) { }
         protected override QuicImplementationProvider UseQuicImplementationProvider => QuicImplementationProviders.MsQuic;
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMockQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_Http3_Mock : HttpClientHandlerTest_Http3
     {
         public SocketsHttpHandlerTest_Http3_Mock(ITestOutputHelper output) : base(output) { }
         protected override QuicImplementationProvider UseQuicImplementationProvider => QuicImplementationProviders.Mock;
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMsQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_HttpClientHandlerTest_Http3_MsQuic : HttpClientHandlerTest
     {
         public SocketsHttpHandlerTest_HttpClientHandlerTest_Http3_MsQuic(ITestOutputHelper output) : base(output) { }
@@ -3168,7 +3168,7 @@ public SocketsHttpHandlerTest_HttpClientHandlerTest_Http3_MsQuic(ITestOutputHelp
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMockQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_HttpClientHandlerTest_Http3_Mock : HttpClientHandlerTest
     {
         public SocketsHttpHandlerTest_HttpClientHandlerTest_Http3_Mock(ITestOutputHelper output) : base(output) { }
@@ -3177,7 +3177,7 @@ public SocketsHttpHandlerTest_HttpClientHandlerTest_Http3_Mock(ITestOutputHelper
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMsQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_Cookies_Http3_MsQuic : HttpClientHandlerTest_Cookies
     {
         public SocketsHttpHandlerTest_Cookies_Http3_MsQuic(ITestOutputHelper output) : base(output) { }
@@ -3186,7 +3186,7 @@ public SocketsHttpHandlerTest_Cookies_Http3_MsQuic(ITestOutputHelper output) : b
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMockQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_Cookies_Http3_Mock : HttpClientHandlerTest_Cookies
     {
         public SocketsHttpHandlerTest_Cookies_Http3_Mock(ITestOutputHelper output) : base(output) { }
@@ -3195,7 +3195,7 @@ public SocketsHttpHandlerTest_Cookies_Http3_Mock(ITestOutputHelper output) : bas
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMsQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_HttpClientHandlerTest_Headers_Http3_MsQuic : HttpClientHandlerTest_Headers
     {
         public SocketsHttpHandlerTest_HttpClientHandlerTest_Headers_Http3_MsQuic(ITestOutputHelper output) : base(output) { }
@@ -3204,7 +3204,7 @@ public SocketsHttpHandlerTest_HttpClientHandlerTest_Headers_Http3_MsQuic(ITestOu
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMockQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandlerTest_HttpClientHandlerTest_Headers_Http3_Mock : HttpClientHandlerTest_Headers
     {
         public SocketsHttpHandlerTest_HttpClientHandlerTest_Headers_Http3_Mock(ITestOutputHelper output) : base(output) { }
@@ -3213,7 +3213,7 @@ public SocketsHttpHandlerTest_HttpClientHandlerTest_Headers_Http3_Mock(ITestOutp
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMsQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandler_HttpClientHandler_Cancellation_Test_Http3_MsQuic : SocketsHttpHandler_Cancellation_Test
     {
         public SocketsHttpHandler_HttpClientHandler_Cancellation_Test_Http3_MsQuic(ITestOutputHelper output) : base(output) { }
@@ -3222,7 +3222,7 @@ public SocketsHttpHandler_HttpClientHandler_Cancellation_Test_Http3_MsQuic(ITest
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMockQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandler_HttpClientHandler_Cancellation_Test_Http3_Mock : SocketsHttpHandler_Cancellation_Test
     {
         public SocketsHttpHandler_HttpClientHandler_Cancellation_Test_Http3_Mock(ITestOutputHelper output) : base(output) { }
@@ -3231,7 +3231,7 @@ public SocketsHttpHandler_HttpClientHandler_Cancellation_Test_Http3_Mock(ITestOu
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMsQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandler_HttpClientHandler_AltSvc_Test_Http3_MsQuic : HttpClientHandler_AltSvc_Test
     {
         public SocketsHttpHandler_HttpClientHandler_AltSvc_Test_Http3_MsQuic(ITestOutputHelper output) : base(output) { }
@@ -3240,7 +3240,7 @@ public SocketsHttpHandler_HttpClientHandler_AltSvc_Test_Http3_MsQuic(ITestOutput
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMockQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandler_HttpClientHandler_AltSvc_Test_Http3_Mock : HttpClientHandler_AltSvc_Test
     {
         public SocketsHttpHandler_HttpClientHandler_AltSvc_Test_Http3_Mock(ITestOutputHelper output) : base(output) { }
@@ -3249,7 +3249,7 @@ public SocketsHttpHandler_HttpClientHandler_AltSvc_Test_Http3_Mock(ITestOutputHe
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMsQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandler_HttpClientHandler_Finalization_Http3_MsQuic : HttpClientHandler_Finalization_Test
     {
         public SocketsHttpHandler_HttpClientHandler_Finalization_Http3_MsQuic(ITestOutputHelper output) : base(output) { }
@@ -3258,18 +3258,14 @@ public SocketsHttpHandler_HttpClientHandler_Finalization_Http3_MsQuic(ITestOutpu
     }
 
     [ConditionalClass(typeof(HttpClientHandlerTestBase), nameof(IsMockQuicSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class SocketsHttpHandler_HttpClientHandler_Finalization_Http3_Mock : HttpClientHandler_Finalization_Test
     {
         public SocketsHttpHandler_HttpClientHandler_Finalization_Http3_Mock(ITestOutputHelper output) : base(output) { }
         protected override Version UseVersion => HttpVersion.Version30;
         protected override QuicImplementationProvider UseQuicImplementationProvider => QuicImplementationProviders.Mock;
     }
 
-    // Define test collection for tests to avoid all other tests.
-    [CollectionDefinition("NoParallelTests", DisableParallelization = true)]
-    public partial class NoParallelTests { }
-
     [ConditionalClass(typeof(PlatformDetection), nameof(PlatformDetection.IsNotBrowser))]
     public abstract class SocketsHttpHandler_RequestValidationTest
     {

src/libraries/System.Net.Http/tests/FunctionalTests/System.Net.Http.Functional.Tests.csproj

@@ -133,6 +133,8 @@
              Link="Common\System\Net\Http\HttpClientHandlerTest.Cookies.cs" />
     <Compile Include="$(CommonTestPath)System\Net\Http\HttpClientHandlerTest.DefaultProxyCredentials.cs"
              Link="Common\System\Net\Http\HttpClientHandlerTest.DefaultProxyCredentials.cs" />
+    <Compile Include="$(CommonTestPath)TestUtilities\System\DisableParallelization.cs"
+             Link="Common\TestUtilities\System\DisableParallelization.cs" />
     <Compile Include="HttpClientHandlerTest.AltSvc.cs" />
     <Compile Include="SocketsHttpHandlerTest.Cancellation.cs" />
     <Compile Include="SocketsHttpHandlerTest.Http2FlowControl.cs" />

src/libraries/System.Net.NameResolution/tests/FunctionalTests/LoggingTest.cs

@@ -13,7 +13,7 @@ namespace System.Net.NameResolution.Tests
 {
     using Configuration = System.Net.Test.Common.Configuration;
 
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public class LoggingTest
     {
         [Fact]

src/libraries/System.Net.NameResolution/tests/FunctionalTests/System.Net.NameResolution.Functional.Tests.csproj

@@ -24,5 +24,7 @@
              Link="Common\System\Net\Configuration.Sockets.cs" />
     <Compile Include="$(CommonTestPath)System\Diagnostics\Tracing\TestEventListener.cs"
              Link="Common\System\Diagnostics\Tracing\TestEventListener.cs" />
+    <Compile Include="$(CommonTestPath)TestUtilities\System\DisableParallelization.cs"
+             Link="Common\TestUtilities\System\DisableParallelization.cs" />
   </ItemGroup>
 </Project>

src/libraries/System.Net.NameResolution/tests/FunctionalTests/TestSettings.cs

@@ -8,9 +8,6 @@
 
 namespace System.Net.NameResolution.Tests
 {
-    [CollectionDefinition("NoParallelTests", DisableParallelization = true)]
-    public partial class NoParallelTests { }
-
     internal static class TestSettings
     {
         // A hostname that will not exist in any DNS caches, forcing some I/O to lookup.

src/libraries/System.Net.Quic/tests/FunctionalTests/MsQuicTests.cs

@@ -20,7 +20,7 @@
 namespace System.Net.Quic.Tests
 {
     [ConditionalClass(typeof(QuicTestBase<MsQuicProviderFactory>), nameof(IsSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public class MsQuicTests : QuicTestBase<MsQuicProviderFactory>
     {
         private static byte[] s_data = Encoding.UTF8.GetBytes("Hello world!");

src/libraries/System.Net.Quic/tests/FunctionalTests/QuicStreamConnectedStreamConformanceTests.cs

@@ -21,7 +21,7 @@ public sealed class MockQuicStreamConformanceTests : QuicStreamConformanceTests
     }
 
     [ConditionalClass(typeof(QuicTestBase<MsQuicProviderFactory>), nameof(QuicTestBase<MsQuicProviderFactory>.IsSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class MsQuicQuicStreamConformanceTests : QuicStreamConformanceTests
     {
         protected override QuicImplementationProvider Provider => QuicImplementationProviders.MsQuic;

src/libraries/System.Net.Quic/tests/FunctionalTests/QuicStreamTests.cs

@@ -994,13 +994,9 @@ public QuicStreamTests_MockProvider(ITestOutputHelper output) : base(output) { }
     }
 
     [ConditionalClass(typeof(QuicTestBase<MsQuicProviderFactory>), nameof(QuicTestBase<MsQuicProviderFactory>.IsSupported))]
-    [Collection("NoParallelTests")]
+    [Collection(nameof(DisableParallelization))]
     public sealed class QuicStreamTests_MsQuicProvider : QuicStreamTests<MsQuicProviderFactory>
     {
         public QuicStreamTests_MsQuicProvider(ITestOutputHelper output) : base(output) { }
     }
-
-    // Define test collection for tests to avoid all other tests.
-    [CollectionDefinition("NoParallelTests", DisableParallelization = true)]
-    public partial class NoParallelTests { }
 }

src/libraries/System.Net.Quic/tests/FunctionalTests/System.Net.Quic.Functional.Tests.csproj

@@ -22,6 +22,7 @@
     <Compile Include="$(CommonTestPath)System\Security\Cryptography\X509Certificates\CertificateAuthority.cs" Link="CommonTest\System\Security\Cryptography\X509Certificates\CertificateAuthority.cs" />
     <Compile Include="$(CommonTestPath)System\Security\Cryptography\X509Certificates\RevocationResponder.cs" Link="CommonTest\System\Security\Cryptography\X509Certificates\RevocationResponder.cs" />
     <Compile Include="$(CommonTestPath)System\Threading\Tasks\TaskTimeoutExtensions.cs" Link="TestCommon\System\Threading\Tasks\TaskTimeoutExtensions.cs" />
+    <Compile Include="$(CommonTestPath)TestUtilities\System\DisableParallelization.cs" Link="Common\TestUtilities\System\DisableParallelization.cs" />
     <Compile Include="..\..\..\System.Net.Security\tests\FunctionalTests\TestHelper.cs" />
   </ItemGroup>
   <ItemGroup>

src/libraries/System.Net.Sockets/tests/FunctionalTests/Connect.cs

@@ -364,7 +364,7 @@ public async Task FailedConnect_ConnectedReturnsFalse()
     // The test class is declared non-parallel because of possible IPv4/IPv6 port-collision on Unix:
     // When running these tests in parallel with other tests, there is some chance that the DualMode client
     // will connect to an IPv4 server of a parallel test case.
-    [Collection(nameof(NoParallelTests))]
+    [Collection(nameof(DisableParallelization))]
     public abstract class Connect_NonParallel<T> : SocketTestHelperBase<T> where T : SocketHelperBase, new()
     {
         protected Connect_NonParallel(ITestOutputHelper output) : base(output)

src/libraries/System.Net.Sockets/tests/FunctionalTests/DisposedSocketTests.cs

@@ -764,7 +764,7 @@ private static void CreateSocketWithDanglingReference()
         }
     }
 
-    [Collection(nameof(NoParallelTests))]
+    [Collection(nameof(DisableParallelization))]
     public class DisposedSocketTestsNonParallel
     {
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsPreciseGcSupported))]