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Fix flaky TestWindowStyle: check only STARTF_USESHOWWINDOW bit, remove ShellExecute cases #125847

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Merged
adamsitnik merged 2 commits into from
Mar 21, 2026
+13 −27
Merged

Fix flaky TestWindowStyle: check only STARTF_USESHOWWINDOW bit, remove ShellExecute cases #125847

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Copilot Mar 20, 2026
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Fix flaky TestWindowStyle: remove ShellExecute logic and check only S…
Copilot Mar 20, 2026
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40 changes: 13 additions & 27 deletions src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.Windows.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@
using System.IO;
using System.Security;
using Microsoft.DotNet.RemoteExecutor;
using Microsoft.DotNet.XUnitExtensions;
using Xunit;

namespace System.Diagnostics.Tests
Expand Down Expand Up @@ -73,45 +72,32 @@ void Cleanup(string username, string _)

[ConditionalTheory(typeof(ProcessStartInfoTests), nameof(IsAdmin_IsNotNano_RemoteExecutorIsSupported))]
[PlatformSpecific(TestPlatforms.Windows)]
[InlineData(ProcessWindowStyle.Normal, true)]
[InlineData(ProcessWindowStyle.Normal, false)]
[InlineData(ProcessWindowStyle.Hidden, true)]
[InlineData(ProcessWindowStyle.Hidden, false)]
[InlineData(ProcessWindowStyle.Minimized, true)]
[InlineData(ProcessWindowStyle.Minimized, false)]
[InlineData(ProcessWindowStyle.Maximized, true)]
[InlineData(ProcessWindowStyle.Maximized, false)]
public void TestWindowStyle(ProcessWindowStyle windowStyle, bool useShellExecute)
[InlineData(ProcessWindowStyle.Normal)]
[InlineData(ProcessWindowStyle.Hidden)]
[InlineData(ProcessWindowStyle.Minimized)]
[InlineData(ProcessWindowStyle.Maximized)]
public void TestWindowStyle(ProcessWindowStyle windowStyle)
{
if (useShellExecute && PlatformDetection.IsMonoRuntime)
(bool expectUsesShowWindow, int expectedWindowFlag) = windowStyle switch
{
// https://github.com/dotnet/runtime/issues/34360
throw new SkipTestException("ShellExecute tries to set STA COM apartment state which is not implemented by Mono.");
}

// "x y" where x is the expected dwFlags & 0x1 result and y is the wShowWindow value
(int expectedDwFlag, int expectedWindowFlag) = windowStyle switch
{
ProcessWindowStyle.Hidden => (1, 0),
ProcessWindowStyle.Minimized => (1, 2),
ProcessWindowStyle.Maximized => (1, 3),
// UseShellExecute always sets the flag but no shell does not for Normal.
_ => useShellExecute ? (1, 1) : (0, 0),
ProcessWindowStyle.Hidden => (true, 0), // SW_HIDE is 0
ProcessWindowStyle.Minimized => (true, 2), // SW_SHOWMINIMIZED is 2
ProcessWindowStyle.Maximized => (true, 3), // SW_SHOWMAXIMIZED is 3
_ => (false, 0),
};

using Process p = CreateProcess((string procArg) =>
{
Interop.GetStartupInfoW(out Interop.STARTUPINFO si);

string[] argSplit = procArg.Split(" ");
int expectedDwFlag = int.Parse(argSplit[0]);
bool expectUsesShowWindow = bool.Parse(argSplit[0]);
short expectedWindowFlag = short.Parse(argSplit[1]);

Assert.Equal(expectedDwFlag, si.dwFlags);
Assert.Equal(expectUsesShowWindow, (si.dwFlags & 0x1) != 0); // STARTF_USESHOWWINDOW is 0x1
Assert.Equal(expectedWindowFlag, si.wShowWindow);
return RemoteExecutor.SuccessExitCode;
}, $"{expectedDwFlag} {expectedWindowFlag}");
p.StartInfo.UseShellExecute = useShellExecute;
}, $"{expectUsesShowWindow} {expectedWindowFlag}");
p.StartInfo.WindowStyle = windowStyle;
p.Start();

Expand Down
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