Fix flaky min rate tests (#2703)

Author: JamesNK

tests/Aspire.Dashboard.Tests/ChannelExtensionsTests.cs

@@ -96,7 +96,7 @@ public async Task GetBatchesAsync_MinReadInterval_WaitForNextRead()
         Assert.Equal(["d", "e", "f"], read2.Single());
 
         var elapsed = stopwatch.Elapsed;
-        Assert.True(elapsed >= minReadInterval, $"Elapsed time {elapsed} should be greater than min read interval {minReadInterval} on read.");
+        CustomAssert.AssertExceedsMinInterval(elapsed, minReadInterval);
 
         channel.Writer.Complete();
         await TaskHelpers.WaitIgnoreCancelAsync(readTask);

tests/Aspire.Dashboard.Tests/CustomAssert.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Xunit;
+
+namespace Aspire.Dashboard.Tests;
+
+public static class CustomAssert
+{
+    public static void AssertExceedsMinInterval(TimeSpan duration, TimeSpan minInterval)
+    {
+        // Timers are not precise, so we allow for a small margin of error.
+        Assert.True(duration >= minInterval.Subtract(TimeSpan.FromMilliseconds(20)), $"Elapsed time {duration} should be greater than min interval {minInterval}.");
+    }
+}

tests/Aspire.Dashboard.Tests/TelemetryRepositoryTests/LogTests.cs

@@ -706,6 +706,6 @@ public async Task Subscription_MultipleUpdates_MinExecuteIntervalApplied()
         Assert.Equal(2, read2);
 
         var elapsed = stopwatch.Elapsed;
-        Assert.True(elapsed >= minExecuteInterval, $"Elapsed time {elapsed} should be greater than min execute interval {minExecuteInterval} on read.");
+        CustomAssert.AssertExceedsMinInterval(elapsed, minExecuteInterval);
     }
 }