feat(tests): enhance telemetry tests with EventCounter listener

Author: BenjaminAbt

Directory.Packages.props

@@ -6,7 +6,7 @@
     <PackageVersion Include="NaughtyStrings" Version="2.4.1" />
   </ItemGroup>
   <ItemGroup Label="Dependencies">
-    <PackageVersion Include="Microsoft.Extensions.Caching.Abstractions" Version="10.0.1" />
+    <PackageVersion Include="Microsoft.Extensions.Caching.Abstractions" Version="8.0.0" />
     <PackageVersion Include="Microsoft.Extensions.Caching.Memory" Version="8.0.1" />
     <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="8.0.1" />
     <PackageVersion Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="8.0.2" />
@@ -71,4 +71,4 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageVersion>
   </ItemGroup>
-</Project>
+</Project>

tests/HttpUserAgentParser.AspNetCore.UnitTests/Telemetry/EventCounterTestListener.cs

@@ -8,6 +8,7 @@ internal sealed class EventCounterTestListener(string eventSourceName) : EventLi
 {
     private readonly string _eventSourceName = eventSourceName;
     private volatile bool _sawEventCounters;
+    private volatile bool _enabled;
 
     protected override void OnEventSourceCreated(EventSource eventSource)
     {
@@ -24,6 +25,8 @@ protected override void OnEventSourceCreated(EventSource eventSource)
             {
                 ["EventCounterIntervalSec"] = "0.1"
             });
+
+        _enabled = true;
     }
 
     protected override void OnEventWritten(EventWrittenEventArgs eventData)
@@ -44,4 +47,15 @@ public bool WaitForCounters(TimeSpan timeout)
 
         return _sawEventCounters;
     }
+
+    public bool WaitUntilEnabled(TimeSpan timeout)
+    {
+        DateTimeOffset start = DateTimeOffset.UtcNow;
+        while (!_enabled && DateTimeOffset.UtcNow - start < timeout)
+        {
+            Thread.Sleep(10);
+        }
+
+        return _enabled;
+    }
 }

tests/HttpUserAgentParser.AspNetCore.UnitTests/Telemetry/HttpUserAgentParserAspNetCoreTelemetryTests.cs

@@ -21,11 +21,15 @@ public void EventCounters_DoNotThrow_WhenEnabled()
 
         DefaultHttpContext ctx = new();
 
-        // present
+        // First call ensures the EventSource gets created (listener enables right after creation).
+        ctx.Request.Headers.UserAgent = "UA";
+        Assert.NotNull(ctx.GetUserAgentString());
+        Assert.True(listener.WaitUntilEnabled(TimeSpan.FromSeconds(2)));
+
+        // Now exercise telemetry-enabled paths.
         ctx.Request.Headers.UserAgent = "UA";
         Assert.NotNull(ctx.GetUserAgentString());
 
-        // missing
         ctx.Request.Headers.Remove("User-Agent");
         Assert.Null(ctx.GetUserAgentString());