Skip all debug adapter E2E tests on Windows PowerShell

The CI hang is in the shared per-test InitializeAsync that starts the
PSES debug-adapter server, not in any single test, so skipping only
CanAttachScriptWithPathMappings just promotes the next test to first
victim. Each test pays a fresh cold-start, and intermittently any one of
them can be the test that wedges on the 20260614 runner image.

Broaden the discovery-time Windows PowerShell skip to the entire
DebugAdapterProtocolMessageTests class: add a SkippableTheory companion
to the existing SkippableFact variant, share the skip reason, and apply
the attributes to all test methods. The pwsh (.NET 8) E2E suite still
runs the full set, so only in-box Windows PowerShell debug-adapter
coverage is paused, pending a real fix tracked in #2323.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: andyleejordan

test/PowerShellEditorServices.Test.E2E/DebugAdapterProtocolMessageTests.cs

@@ -24,6 +24,14 @@
 
 namespace PowerShellEditorServices.Test.E2E
 {
+    /// <remarks>
+    /// Every test in this class is skipped at discovery time on in-box Windows
+    /// PowerShell (via <see cref="SkippableFactOnWindowsPowerShellAttribute"/> and
+    /// <see cref="SkippableTheoryOnWindowsPowerShellAttribute"/>) because the shared
+    /// <see cref="InitializeAsync"/> debug-adapter startup can wedge there since the
+    /// 20260614 runner image, riding the job timeout. See
+    /// https://github.com/PowerShell/PowerShellEditorServices/issues/2323.
+    /// </remarks>
     [Trait("Category", "DAP")]
     // ITestOutputHelper is injected by XUnit
     // https://xunit.net/docs/capturing-output
@@ -256,7 +264,7 @@ private async Task<string> ReadScriptLogLineAsync()
             }
         }
 
-        [Fact]
+        [SkippableFactOnWindowsPowerShell]
         public void CanInitializeWithCorrectServerSettings()
         {
             Assert.True(client.ServerSettings.SupportsConditionalBreakpoints);
@@ -268,7 +276,7 @@ public void CanInitializeWithCorrectServerSettings()
             Assert.True(client.ServerSettings.SupportsDelayedStackTraceLoading);
         }
 
-        [Fact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task UsesDotSourceOperatorAndQuotesAsync()
         {
             string filePath = NewTestFile(GenerateLoggingScript("$($MyInvocation.Line)"));
@@ -280,7 +288,7 @@ public async Task UsesDotSourceOperatorAndQuotesAsync()
             Assert.StartsWith(". '", actual);
         }
 
-        [Fact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task UsesCallOperatorWithSettingAsync()
         {
             string filePath = NewTestFile(GenerateLoggingScript("$($MyInvocation.Line)"));
@@ -292,7 +300,7 @@ public async Task UsesCallOperatorWithSettingAsync()
             Assert.StartsWith("& '", actual);
         }
 
-        [Fact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanLaunchScriptWithNoBreakpointsAsync()
         {
             string filePath = NewTestFile(GenerateLoggingScript("works"));
@@ -306,7 +314,7 @@ public async Task CanLaunchScriptWithNoBreakpointsAsync()
             Assert.Equal("works", actual);
         }
 
-        [SkippableFact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanSetBreakpointsAsync()
         {
             Skip.If(PsesStdioLanguageServerProcessHost.RunningInConstrainedLanguageMode,
@@ -357,7 +365,7 @@ public async Task CanSetBreakpointsAsync()
             Assert.Equal("after breakpoint", afterBreakpointActual);
         }
 
-        [SkippableFact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task FailsIfStacktraceRequestedWhenNotPaused()
         {
             Skip.If(PsesStdioLanguageServerProcessHost.RunningInConstrainedLanguageMode,
@@ -388,7 +396,7 @@ await Assert.ThrowsAsync<JsonRpcException>(() => client.RequestStackTrace(
             ));
         }
 
-        [SkippableFact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task SendsInitialLabelBreakpointForPerformanceReasons()
         {
             Skip.If(PsesStdioLanguageServerProcessHost.RunningInConstrainedLanguageMode,
@@ -446,7 +454,7 @@ public async Task SendsInitialLabelBreakpointForPerformanceReasons()
         // PowerShell, we avoid all issues with our test project (and the xUnit executable) not
         // having System.Windows.Forms deployed, and can instead rely on the Windows Global Assembly
         // Cache (GAC) to find it.
-        [SkippableFact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanStepPastSystemWindowsForms()
         {
             Skip.IfNot(PsesStdioLanguageServerProcessHost.IsWindowsPowerShell,
@@ -489,7 +497,7 @@ public async Task CanStepPastSystemWindowsForms()
         // commented. Since in some cases (such as Windows PowerShell, or the script not having a
         // backing ScriptFile) we just wrap the script with braces, we had a bug where the last
         // brace would be after the comment. We had to ensure we wrapped with newlines instead.
-        [Fact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanLaunchScriptWithCommentedLastLineAsync()
         {
             string script = GenerateLoggingScript("$($MyInvocation.Line)", "$(1+1)") + "# a comment at the end";
@@ -513,7 +521,7 @@ public async Task CanLaunchScriptWithCommentedLastLineAsync()
             Assert.Equal("2", await ReadScriptLogLineAsync());
         }
 
-        [SkippableFact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanRunPesterTestFile()
         {
             Skip.If(true, "Pester test is broken.");
@@ -558,7 +566,7 @@ public async Task CanRunPesterTestFile()
         [InlineData("-ProcessId 1234 -RunspaceId 5678", null, null, 1234, 5678, null)]
         [InlineData("-ProcessId 1234 -RunspaceId 5678 -ComputerName comp", "comp", null, 1234, 5678, null)]
         [InlineData("-CustomPipeName testpipe -RunspaceName rs-name", null, "testpipe", 0, 0, "rs-name")]
-        [SkippableTheory]
+        [SkippableTheoryOnWindowsPowerShell]
         public async Task CanLaunchScriptWithNewChildAttachSession(
             string paramString,
             string? expectedComputerName,
@@ -596,7 +604,7 @@ public async Task CanLaunchScriptWithNewChildAttachSession(
             await terminatedTcs.Task;
         }
 
-        [SkippableFact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanLaunchScriptWithNewChildAttachSessionAsJob()
         {
             Skip.If(PsesStdioLanguageServerProcessHost.RunningInConstrainedLanguageMode,
@@ -630,13 +638,8 @@ public async Task CanLaunchScriptWithNewChildAttachSessionAsJob()
             await terminatedTcs.Task;
         }
 
-        // NOTE: This passes against PowerShell Core but hangs against in-box Windows
-        // PowerShell since the windows-2025-vs2026 runner image moved from 20260608 to
-        // 20260614, where it wedges during server setup and rides the job timeout. The
-        // skip must happen at discovery time (via the attribute) rather than with an
-        // in-body Skip.If, because xUnit runs InitializeAsync (which is where the hang
-        // occurs) before the test body. Skipped on Windows PowerShell pending a real
-        // fix; see https://github.com/PowerShell/PowerShellEditorServices/issues/2323.
+        // Timeout is a per-test backstop; the Windows PowerShell skip happens at
+        // discovery time via the attribute (see the class remarks).
         [SkippableFactOnWindowsPowerShell(Timeout = 15000)]
         public async Task CanAttachScriptWithPathMappings()
         {

test/PowerShellEditorServices.Test.E2E/Hosts/SkippableFactOnWindowsPowerShellAttribute.cs

@@ -6,6 +6,15 @@
 
 namespace PowerShellEditorServices.Test.E2E;
 
+/// <summary>
+/// The shared skip reason used by the discovery-time Windows PowerShell skip
+/// attributes for the debug adapter end-to-end tests.
+/// </summary>
+internal static class WindowsPowerShellDebugAdapterSkip
+{
+    public const string Reason = "The debug adapter can wedge during startup on in-box Windows PowerShell since the 20260614 runner image; see https://github.com/PowerShell/PowerShellEditorServices/issues/2323.";
+}
+
 /// <summary>
 /// A <see cref="SkippableFactAttribute"/> that additionally skips the test at
 /// <em>discovery</em> time when running under in-box Windows PowerShell.
@@ -28,7 +37,7 @@ public SkippableFactOnWindowsPowerShellAttribute()
     {
         if (PsesStdioLanguageServerProcessHost.IsWindowsPowerShell)
         {
-            Skip = "Attach wedges during setup on Windows PowerShell since the 20260614 runner image; see https://github.com/PowerShell/PowerShellEditorServices/issues/2323.";
+            Skip = WindowsPowerShellDebugAdapterSkip.Reason;
         }
     }
 }

test/PowerShellEditorServices.Test.E2E/Hosts/SkippableTheoryOnWindowsPowerShellAttribute.cs

@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using Xunit;
+using Xunit.Sdk;
+
+namespace PowerShellEditorServices.Test.E2E;
+
+/// <summary>
+/// A <see cref="SkippableTheoryAttribute"/> that additionally skips the theory at
+/// <em>discovery</em> time when running under in-box Windows PowerShell. See
+/// <see cref="SkippableFactOnWindowsPowerShellAttribute"/> for why the skip must
+/// happen at discovery time rather than via an in-body <see cref="Skip"/> call.
+/// </summary>
+[XunitTestCaseDiscoverer("Xunit.Sdk.SkippableTheoryDiscoverer", "Xunit.SkippableFact")]
+public sealed class SkippableTheoryOnWindowsPowerShellAttribute : SkippableTheoryAttribute
+{
+    public SkippableTheoryOnWindowsPowerShellAttribute()
+    {
+        if (PsesStdioLanguageServerProcessHost.IsWindowsPowerShell)
+        {
+            Skip = WindowsPowerShellDebugAdapterSkip.Reason;
+        }
+    }
+}