Fix flaky tests (#2457)

Attempt to fix flaky tests.

Author: martincostello

test/Polly.Core.Tests/Issues/IssuesTests.InfiniteRetry_2163.cs

@@ -5,7 +5,7 @@ namespace Polly.Core.Tests.Issues;
 
 public partial class IssuesTests
 {
-    [Fact(Timeout = 15_000)]
+    [Fact(Timeout = 30_000)]
     public async Task InfiniteRetry_Delay_Does_Not_Overflow_2163()
     {
         // Arrange
@@ -35,7 +35,8 @@ public async Task InfiniteRetry_Delay_Does_Not_Overflow_2163()
         var strategy = new RetryResilienceStrategy<bool>(options, timeProvider, telemetry);
         var pipeline = strategy.AsPipeline();
 
-        using var cts = new CancellationTokenSource(Debugger.IsAttached ? TimeSpan.MaxValue : TimeSpan.FromSeconds(10));
+        using var cts = new CancellationTokenSource(
+            Debugger.IsAttached ? TimeSpan.MaxValue : TimeSpan.FromSeconds(20));
 
         // Act
         var executing = pipeline.ExecuteAsync((_) =>

test/Polly.Specs/Timeout/TimeoutSpecsBase.cs

@@ -8,6 +8,7 @@ namespace Polly.Specs.Timeout;
 /// For tests, rather than letting .NET's timers drive the timing out of CancellationTokens, we override SystemClock.CancelTokenAfter and SystemClock.Sleep to make the tests run fast.
 /// </remarks>
 /// </summary>
+[Collection(Constants.SystemClockDependentTestCollection)]
 public abstract class TimeoutSpecsBase : IDisposable
 {
     // xUnit creates a new class instance per test, so these variables are isolated per test.

test/Polly.Specs/Utilities/SystemClockSpecs.cs

@@ -1,18 +1,29 @@
 namespace Polly.Specs.Utilities;
 
+[Collection(Constants.SystemClockDependentTestCollection)]
 public class SystemClockSpecs
 {
+    private readonly Action<TimeSpan, CancellationToken> _sleep;
+    private readonly Func<TimeSpan, CancellationToken, Task> _sleepAsync;
+
+    public SystemClockSpecs()
+    {
+        SystemClock.Reset();
+        _sleep = SystemClock.Sleep;
+        _sleepAsync = SystemClock.SleepAsync;
+    }
+
     [Fact]
     public void Sleep_ShouldNotThrow_WhenCancellationNotRequested() =>
-        SystemClock.Sleep.Invoking(s =>
+        _sleep.Invoking(s =>
         {
             using var cts = new CancellationTokenSource();
             s(TimeSpan.FromMilliseconds(1), cts.Token);
         }).Should().NotThrow();
 
     [Fact]
     public void Sleep_ShouldThrow_WhenCancellationRequested() =>
-        SystemClock.Sleep.Invoking(s =>
+        _sleep.Invoking(s =>
         {
             using var cts = new CancellationTokenSource();
             cts.Cancel();
@@ -21,15 +32,15 @@ public void Sleep_ShouldThrow_WhenCancellationRequested() =>
 
     [Fact]
     public async Task SleepAsync_ShouldNotThrow_WhenCancellationNotRequested() =>
-        await SystemClock.SleepAsync.Invoking(async s =>
+        await _sleepAsync.Invoking(async s =>
         {
             using var cts = new CancellationTokenSource();
             await s(TimeSpan.FromMilliseconds(1), cts.Token);
         }).Should().NotThrowAsync();
 
     [Fact]
     public async Task SleepAsync_ShouldThrow_WhenCancellationRequested() =>
-        await SystemClock.SleepAsync.Invoking(async s =>
+        await _sleepAsync.Invoking(async s =>
         {
             using var cts = new CancellationTokenSource();
             cts.Cancel();