From 34c94225216955ad9a91eba7dd1449e8f14cc496 Mon Sep 17 00:00:00 2001
From: Koundinya Veluri <kouvel@microsoft.com>
Date: Tue, 19 Feb 2019 13:30:41 -0800
Subject: [PATCH 1/3] Add a timer test

- Separated from https://github.com/dotnet/corefx/pull/35502
- Added test from https://github.com/dotnet/corert/pull/7069 to CoreFX
---
 .../tests/System.Threading.Timer.Tests.csproj |  5 ++
 .../tests/TimerFiringTests.cs                 | 54 +++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj b/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj
index 2bb3c8ebefd5..df858bdb16bc 100644
--- a/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj
+++ b/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj
@@ -12,4 +12,9 @@
   <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp'">
     <Compile Include="TimerDisposeTests.cs" />
   </ItemGroup>
+  <ItemGroup>
+    <Compile Include="$(CommonTestPath)\System\Threading\ThreadTestHelpers.cs">
+      <Link>CommonTest\System\Threading\ThreadTestHelpers.cs</Link>
+    </Compile>
+  </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/src/System.Threading.Timer/tests/TimerFiringTests.cs b/src/System.Threading.Timer/tests/TimerFiringTests.cs
index 00006f68f0df..3efd7fb17876 100644
--- a/src/System.Threading.Timer/tests/TimerFiringTests.cs
+++ b/src/System.Threading.Timer/tests/TimerFiringTests.cs
@@ -10,6 +10,7 @@
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Threading.Tests;
 using Xunit;
 using Xunit.Sdk;
 
@@ -337,4 +338,57 @@ private static async Task PeriodAsync(int period, int iterations)
             await tcs.Task.ConfigureAwait(false);
         }
     }
+
+    [Fact]
+    public void TimersCreatedConcurrentlyOnDifferentThreadsAllFire()
+    {
+        int processorCount = Environment.ProcessorCount;
+
+        int timerTickCount = 0;
+        TimerCallback timerCallback = data => Interlocked.Increment(ref timerTickCount);
+
+        var threadStarted = new AutoResetEvent(false);
+        var createTimers = new ManualResetEvent(false);
+        var timers = new Timer[processorCount];
+        Action<object> createTimerThreadStart = data =>
+        {
+            int i = (int)data;
+            var sw = new Stopwatch();
+            threadStarted.Set();
+            createTimers.WaitOne();
+
+            // Use the CPU a bit around creating the timer to try to have some of these threads run concurrently
+            sw.Restart();
+            do
+            {
+                Thread.SpinWait(1000);
+            } while (sw.ElapsedMilliseconds < 10);
+
+            timers[i] = new Timer(timerCallback, null, 1, Timeout.Infinite);
+
+            // Use the CPU a bit around creating the timer to try to have some of these threads run concurrently
+            sw.Restart();
+            do
+            {
+                Thread.SpinWait(1000);
+            } while (sw.ElapsedMilliseconds < 10);
+        };
+
+        var waitsForThread = new Action[timers.Length];
+        for (int i = 0; i < timers.Length; ++i)
+        {
+            var t = ThreadTestHelpers.CreateGuardedThread(out waitsForThread[i], createTimerThreadStart);
+            t.IsBackground = true;
+            t.Start(i);
+            threadStarted.CheckedWait();
+        }
+
+        createTimers.Set();
+        ThreadTestHelpers.WaitForCondition(() => timerTickCount == timers.Length);
+
+        foreach (var waitForThread in waitsForThread)
+        {
+            waitForThread();
+        }
+    }
 }

From 48d32fbed4e4c33e8a2684f8646a8bc72b12d484 Mon Sep 17 00:00:00 2001
From: Koundinya Veluri <kouvel@microsoft.com>
Date: Fri, 5 Apr 2019 03:27:28 -0700
Subject: [PATCH 2/3] Address feedback

---
 src/System.Threading.Timer/tests/TimerFiringTests.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/System.Threading.Timer/tests/TimerFiringTests.cs b/src/System.Threading.Timer/tests/TimerFiringTests.cs
index 3efd7fb17876..375df334653b 100644
--- a/src/System.Threading.Timer/tests/TimerFiringTests.cs
+++ b/src/System.Threading.Timer/tests/TimerFiringTests.cs
@@ -345,7 +345,7 @@ public void TimersCreatedConcurrentlyOnDifferentThreadsAllFire()
         int processorCount = Environment.ProcessorCount;
 
         int timerTickCount = 0;
-        TimerCallback timerCallback = data => Interlocked.Increment(ref timerTickCount);
+        TimerCallback timerCallback = _ => Interlocked.Increment(ref timerTickCount);
 
         var threadStarted = new AutoResetEvent(false);
         var createTimers = new ManualResetEvent(false);

From 95454263558e8719b794e97f1caa390d97ff2cbc Mon Sep 17 00:00:00 2001
From: Koundinya Veluri <kouvel@microsoft.com>
Date: Fri, 5 Apr 2019 04:35:24 -0700
Subject: [PATCH 3/3] Include remote executor for project

---
 .../tests/System.Threading.Timer.Tests.csproj                    | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj b/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj
index df858bdb16bc..d4b83860cfa4 100644
--- a/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj
+++ b/src/System.Threading.Timer/tests/System.Threading.Timer.Tests.csproj
@@ -3,6 +3,7 @@
     <ProjectGuid>{ac20a28f-fda8-45e8-8728-058ead16e44c}</ProjectGuid>
     <Configurations>netcoreapp-Debug;netcoreapp-Release;netstandard-Debug;netstandard-Release</Configurations>
     <TestRuntime>true</TestRuntime>
+    <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="TimerConstructorTests.cs" />