Add regression test for System.Windows.Forms bug

test/PowerShellEditorServices.Test.Shared/Debugging/FormsTest.ps1

@@ -0,0 +1,5 @@
+Add-Type -AssemblyName "System.Windows.Forms"
+$before = "before"
+$form = New-Object System.Windows.Forms.Form
+$after = "after"
+Write-Host "$before, $form, $after"

test/PowerShellEditorServices.Test/Debugging/DebugServiceTests.cs

@@ -32,6 +32,16 @@ public class DebugServiceTests : IDisposable
         private AsyncQueue<SessionStateChangedEventArgs> sessionStateQueue =
             new AsyncQueue<SessionStateChangedEventArgs>();
 
+        private ScriptFile GetDebugScript(string fileName)
+        {
+            return this.workspace.GetFile(
+                TestUtilities.NormalizePath(Path.Combine(
+                    Path.GetDirectoryName(typeof(DebugServiceTests).Assembly.Location),
+                    "../../../../PowerShellEditorServices.Test.Shared/Debugging",
+                    fileName
+                )));
+        }
+
         public DebugServiceTests()
         {
             var logger = NullLogger.Instance;
@@ -41,18 +51,9 @@ public DebugServiceTests()
 
             this.workspace = new WorkspaceService(NullLoggerFactory.Instance);
 
-            // Load the test debug file
-            this.debugScriptFile =
-                this.workspace.GetFile(
-                    TestUtilities.NormalizePath(Path.Combine(
-                        Path.GetDirectoryName(typeof(DebugServiceTests).Assembly.Location),
-                        "../../../../PowerShellEditorServices.Test.Shared/Debugging/VariableTest.ps1")));
-
-            this.variableScriptFile =
-                this.workspace.GetFile(
-                    TestUtilities.NormalizePath(Path.Combine(
-                        Path.GetDirectoryName(typeof(DebugServiceTests).Assembly.Location),
-                        "../../../../PowerShellEditorServices.Test.Shared/Debugging/VariableTest.ps1")));
+            // Load the test debug files
+            this.debugScriptFile = GetDebugScript("DebugTest.ps1");
+            this.variableScriptFile = GetDebugScript("VariableTest.ps1");
 
             this.debugService = new DebugService(
                 this.powerShellContext,
@@ -65,13 +66,6 @@ public DebugServiceTests()
 
             this.debugService.DebuggerStopped += debugService_DebuggerStopped;
             this.debugService.BreakpointUpdated += debugService_BreakpointUpdated;
-
-            // Load the test debug file
-            this.debugScriptFile =
-                this.workspace.GetFile(
-                    TestUtilities.NormalizePath(Path.Combine(
-                        Path.GetDirectoryName(typeof(DebugServiceTests).Assembly.Location),
-                        "../../../../PowerShellEditorServices.Test.Shared/Debugging/DebugTest.ps1")));
         }
 
         async void powerShellContext_SessionStateChanged(object sender, SessionStateChangedEventArgs e)
@@ -123,11 +117,7 @@ public async Task DebuggerAcceptsScriptArgs(string[] args)
             // The path is intentionally odd (some escaped chars but not all) because we are testing
             // the internal path escaping mechanism - it should escape certains chars ([, ] and space) but
             // it should not escape already escaped chars.
-            ScriptFile debugWithParamsFile =
-                this.workspace.GetFile(
-                    TestUtilities.NormalizePath(Path.Combine(
-                        Path.GetDirectoryName(typeof(DebugServiceTests).Assembly.Location),
-                        "../../../../PowerShellEditorServices.Test.Shared/Debugging/Debug W&ith Params [Test].ps1")));
+            ScriptFile debugWithParamsFile = GetDebugScript("Debug W&ith Params [Test].ps1");
 
             await this.debugService.SetLineBreakpointsAsync(
                 debugWithParamsFile,
@@ -889,7 +879,7 @@ await this.debugService.SetLineBreakpointsAsync(
 
             var nullStringVar = variables.FirstOrDefault(v => v.Name == "$nullString");
             Assert.NotNull(nullStringVar);
-            Assert.True("[NullString]".Equals(nullStringVar.ValueString));
+            Assert.Equal("[NullString]", nullStringVar.ValueString);
             Assert.True(nullStringVar.IsExpandable);
 
             // Abort script execution early and wait for completion
@@ -973,6 +963,7 @@ await this.debugService.SetLineBreakpointsAsync(
 
         // Verifies fix for issue #86, $proc = Get-Process foo displays just the ETS property set
         // and not all process properties.
+        [Trait("Category", "DebugService")]
         [Fact]
         public async Task DebuggerVariableProcessObjDisplaysCorrectly()
         {
@@ -1005,6 +996,55 @@ await this.debugService.SetLineBreakpointsAsync(
             await executeTask.ConfigureAwait(false);
         }
 
+        // This is a regression test for a bug where user code causes a new synchronization context
+        // to be created, breaking the extension. It's most evident when debugging PowerShell
+        // scripts that use System.Windows.Forms. It required fixing both Editor Services and
+        // OmniSharp.
+        //
+        // This test depends on PowerShell being able to load System.Windows.Forms, which only works
+        // reliably with Windows PowerShell. It works with PowerShell Core in the real-world;
+        // however, our host executable is xUnit, not PowerShell. So by restricting to Windows
+        // 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.
+        [Trait("Category", "DebugService")]
+        [SkippableFact]
+        public async Task DebuggerStepsPastSystemWindowsForms()
+        {
+            Skip.If(!VersionUtils.IsPS5);
+
+            ScriptFile formsFile = GetDebugScript("FormsTest.ps1");
+
+            await debugService.SetCommandBreakpointsAsync(
+                new [] { CommandBreakpointDetails.Create("Write-Host") }).ConfigureAwait(false);
+
+            Task executeTask = powerShellContext.ExecuteScriptWithArgsAsync(formsFile.FilePath);
+
+            // Wait for function breakpoint to hit
+            await AssertDebuggerStopped(formsFile.FilePath, 5).ConfigureAwait(false);
+
+            StackFrameDetails[] stackFrames = debugService.GetStackFrames();
+            VariableDetailsBase[] variables =
+                debugService.GetVariables(stackFrames[0].LocalVariables.Id);
+
+            // Verify $before, $form, and $after vars exist
+            var before = variables.FirstOrDefault(v => v.Name == "$before");
+            Assert.NotNull(before);
+            Assert.Equal("\"before\"", before.ValueString);
+
+            var form = variables.FirstOrDefault(v => v.Name == "$form");
+            Assert.NotNull(form);
+            Assert.StartsWith("System.Windows.Forms.Form", form.ValueString);
+
+            var after = variables.FirstOrDefault(v => v.Name == "$after");
+            Assert.NotNull(after);
+            Assert.Equal("\"after\"", after.ValueString);
+
+            // Abort script execution early and wait for completion
+            debugService.Abort();
+            await executeTask.ConfigureAwait(false);
+        }
+
         public async Task AssertDebuggerPaused()
         {
             DebuggerStoppedEventArgs eventArgs =