Fix flaky ResourceHealthCheckService test. (#6730)

Introduce time provider to the resource health check service and use channels for sampling loop time.

src/Aspire.Hosting/DistributedApplicationBuilder.cs

@@ -132,6 +132,8 @@ public DistributedApplicationBuilder(DistributedApplicationOptions options)
         LogBuilderConstructing(options, innerBuilderOptions);
         _innerBuilder = new HostApplicationBuilder(innerBuilderOptions);
 
+        _innerBuilder.Services.AddSingleton(TimeProvider.System);
+
         _innerBuilder.Logging.AddFilter("Microsoft.Hosting.Lifetime", LogLevel.Warning);
         _innerBuilder.Logging.AddFilter("Microsoft.AspNetCore.Server.Kestrel", LogLevel.Error);
         _innerBuilder.Logging.AddFilter("Aspire.Hosting.Dashboard", LogLevel.Error);

src/Aspire.Hosting/Health/ResourceHealthCheckService.cs

@@ -11,7 +11,7 @@
 
 namespace Aspire.Hosting.Health;
 
-internal class ResourceHealthCheckService(ILogger<ResourceHealthCheckService> logger, ResourceNotificationService resourceNotificationService, HealthCheckService healthCheckService, IServiceProvider services, IDistributedApplicationEventing eventing) : BackgroundService
+internal class ResourceHealthCheckService(ILogger<ResourceHealthCheckService> logger, ResourceNotificationService resourceNotificationService, HealthCheckService healthCheckService, IServiceProvider services, IDistributedApplicationEventing eventing, TimeProvider timeProvider) : BackgroundService
 {
     private readonly Dictionary<string, ResourceEvent> _latestEvents = new();
 
@@ -62,7 +62,7 @@ await eventing.PublishAsync(
 
         var registrationKeysToCheck = annotations.DistinctBy(a => a.Key).Select(a => a.Key).ToFrozenSet();
 
-        using var timer = new PeriodicTimer(TimeSpan.FromSeconds(5));
+        using var timer = new PeriodicTimer(TimeSpan.FromSeconds(5), timeProvider);
 
         do
         {
@@ -144,11 +144,11 @@ await resourceNotificationService.PublishUpdateAsync(resource, s =>
 
         async Task SlowDownMonitoringAsync(ResourceEvent lastEvent, CancellationToken cancellationToken)
         {
-            var releaseAfter = DateTime.Now.AddSeconds(30);
+            var releaseAfter = timeProvider.GetUtcNow().AddSeconds(30);
 
             // If we've waited for 30 seconds, or we received an updated event, or the health status is no longer
             // healthy then we stop slowing down the monitoring loop.
-            while (DateTime.Now < releaseAfter && _latestEvents[lastEvent.Resource.Name] == lastEvent && lastEvent.Snapshot.HealthStatus == HealthStatus.Healthy)
+            while (timeProvider.GetUtcNow() < releaseAfter && _latestEvents[lastEvent.Resource.Name] == lastEvent && lastEvent.Snapshot.HealthStatus == HealthStatus.Healthy)
             {
                 await Task.Delay(1000, cancellationToken).ConfigureAwait(false);
             }

tests/Aspire.Hosting.Tests/Aspire.Hosting.Tests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>$(DefaultTargetFramework)</TargetFramework>
@@ -19,6 +19,7 @@
 
     <PackageReference Include="Microsoft.Extensions.Http.Resilience" />
     <PackageReference Include="Microsoft.Extensions.Diagnostics.Testing" />
+    <PackageReference Include="Microsoft.Extensions.TimeProvider.Testing" />
 
     <Compile Include="$(TestsSharedDir)Logging\*.cs" LinkBase="shared/Logging" />
     <Compile Include="$(TestsSharedDir)ConsoleLogging\*.cs" LinkBase="shared" />

tests/Aspire.Hosting.Tests/Health/ResourceHealthCheckServiceTests.cs

@@ -2,10 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
+using System.Threading.Channels;
 using Aspire.Hosting.Utils;
 using Microsoft.AspNetCore.InternalTesting;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Diagnostics.HealthChecks;
+using Microsoft.Extensions.Time.Testing;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -129,12 +131,14 @@ public async Task HealthCheckIntervalDoesNotSlowBeforeSteadyHealthyState()
     {
         using var builder = TestDistributedApplicationBuilder.Create(testOutputHelper);
 
-        AutoResetEvent? are = null;
+        var channel = Channel.CreateUnbounded<DateTimeOffset>();
 
-        builder.Services.AddHealthChecks().AddCheck("resource_check", () =>
-        {
-            are?.Set();
+        var timeProvider = new FakeTimeProvider(DateTimeOffset.Now);
 
+        builder.Services.AddSingleton<TimeProvider>(timeProvider);
+        builder.Services.AddHealthChecks().AddAsyncCheck("resource_check", async () =>
+        {
+            await channel.Writer.WriteAsync(timeProvider.GetUtcNow());
             return HealthCheckResult.Unhealthy();
         });
 
@@ -154,21 +158,18 @@ await rns.PublishUpdateAsync(resource.Resource, s => s with
         }).DefaultTimeout();
         await rns.WaitForResourceAsync(resource.Resource.Name, KnownResourceStates.Running, abortTokenSource.Token).DefaultTimeout();
 
-        are = new AutoResetEvent(false);
+        var firstCheck = await channel.Reader.ReadAsync(abortTokenSource.Token).DefaultTimeout();
+        timeProvider.Advance(TimeSpan.FromSeconds(5));
 
-        // Allow one event to through since it could be half way through.
-        are.WaitOne();
-
-        var stopwatch = Stopwatch.StartNew();
-        are.WaitOne();
-        stopwatch.Stop();
+        var secondCheck = await channel.Reader.ReadAsync(abortTokenSource.Token).DefaultTimeout();
+        timeProvider.Advance(TimeSpan.FromSeconds(5));
 
-        // When not in a healthy state the delay should be ~3 seconds but
-        // we'll check for 10 seconds to make sure we haven't got down
-        // the 30 second slow path.
-        Assert.True(stopwatch.ElapsedMilliseconds < 10000);
+        var thirdCheck = await channel.Reader.ReadAsync(abortTokenSource.Token).DefaultTimeout();
 
         await app.StopAsync(abortTokenSource.Token).DefaultTimeout();
+
+        var duration = thirdCheck - firstCheck;
+        Assert.Equal(TimeSpan.FromSeconds(10), duration);
     }
 
     [Fact]