System.Diagnostics.Tests.ProcessTests.TestToString_OnExitedProcess failing in the CI

[tarekgh]

https://dev.azure.com/dnceng/public/_build/results?buildId=1268768&view=logs&j=1422aa79-6880-5d83-e13f-65c73e5c446b&t=f314303b-c6ab-51e8-2c96-4cbe16c1a0a2

https://helixre8s23ayyeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-pull-56504-merge-b7005c257cb84dc688/System.Diagnostics.Process.Tests/console.0ad0143c.log?sv=2019-07-07&se=2021-08-19T22%3A06%3A57Z&sr=c&sp=rl&sig=2CWyX9R8Vs5TyDW7fMIet3VfEWnMAX6eeyqKDZ6tsB4%3D

C:\h\w\A9F70974\w\A2CA08DC\e>"C:\h\w\A9F70974\p\dotnet.exe" exec --runtimeconfig System.Diagnostics.Process.Tests.runtimeconfig.json --depsfile System.Diagnostics.Process.Tests.deps.json xunit.console.dll System.Diagnostics.Process.Tests.dll -xml testResults.xml -nologo -nocolor -notrait category=IgnoreForCI -notrait category=OuterLoop -notrait category=failing  
  Discovering: System.Diagnostics.Process.Tests (method display = ClassAndMethod, method display options = None)
  Discovered:  System.Diagnostics.Process.Tests (found 254 of 278 test cases)
  Starting:    System.Diagnostics.Process.Tests (parallel test collections = on, max threads = 2)
    System.Diagnostics.Tests.ProcessStartInfoTests.ShellExecute_Nano_Fails_Start [SKIP]
      Condition(s) not met: "IsWindowsNanoServer"
    System.Diagnostics.Tests.ProcessTests.TestToString_OnExitedProcess [FAIL]
      Assert.Equal() Failure
                                       ? (pos 26)
      Expected: ....Diagnostics.Process
      Actual:   ....Diagnostics.Process (dotnet)
                                       ? (pos 26)
      Stack Trace:
        /_/src/libraries/System.Diagnostics.Process/tests/ProcessTests.cs(492,0): at System.Diagnostics.Tests.ProcessTests.TestToString_OnExitedProcess()
Invalid number of parameters

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Issue Details

---

https://helixre8s23ayyeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-pull-56504-merge-b7005c257cb84dc688/System.Diagnostics.Process.Tests/console.0ad0143c.log?sv=2019-07-07&se=2021-08-19T22%3A06%3A57Z&sr=c&sp=rl&sig=2CWyX9R8Vs5TyDW7fMIet3VfEWnMAX6eeyqKDZ6tsB4%3D

C:\h\w\A9F70974\w\A2CA08DC\e>"C:\h\w\A9F70974\p\dotnet.exe" exec --runtimeconfig System.Diagnostics.Process.Tests.runtimeconfig.json --depsfile System.Diagnostics.Process.Tests.deps.json xunit.console.dll System.Diagnostics.Process.Tests.dll -xml testResults.xml -nologo -nocolor -notrait category=IgnoreForCI -notrait category=OuterLoop -notrait category=failing  
  Discovering: System.Diagnostics.Process.Tests (method display = ClassAndMethod, method display options = None)
  Discovered:  System.Diagnostics.Process.Tests (found 254 of 278 test cases)
  Starting:    System.Diagnostics.Process.Tests (parallel test collections = on, max threads = 2)
    System.Diagnostics.Tests.ProcessStartInfoTests.ShellExecute_Nano_Fails_Start [SKIP]
      Condition(s) not met: "IsWindowsNanoServer"
    System.Diagnostics.Tests.ProcessTests.TestToString_OnExitedProcess [FAIL]
      Assert.Equal() Failure
                                       ? (pos 26)
      Expected: ....Diagnostics.Process
      Actual:   ....Diagnostics.Process (dotnet)
                                       ? (pos 26)
      Stack Trace:
        /_/src/libraries/System.Diagnostics.Process/tests/ProcessTests.cs(492,0): at System.Diagnostics.Tests.ProcessTests.TestToString_OnExitedProcess()
Invalid number of parameters

Author:	tarekgh
Assignees:	-
Labels:	area-System.Diagnostics.Process
Milestone:	-

[danmoseley]

Before calling ToString() the test calls WaitForExit(), which it asserted returned true. WaitForExit() is implemented by getting the process handle and waiting for it to be signaled.

Inside ToString(), the code calls ProcessManager.GetProcessInfo(..) --> NtProcessInfoHelper.GetProcessInfos(processId) --> NtQuerySystemInformation passing SystemProcessInformation (0x05) which returns an array of SYSTEM_PROCESS_INFORMATION. If the PID is in that array, it uses the process name (from ImageName in the struct) to append to the result.

This failure suggests that despite the process handle being signaled, NtQuerySystemInformation returned it. We know this is flaky, since it passed when we committed this test.

In the absence of better ideas, short of a sleep, we should modify the test to accept either output since it really doesn't matter much.