Warn on improperly disposed tests. (#18594)

Content.IntegrationTests/PoolManager.cs

@@ -947,6 +947,10 @@ public sealed class PairTracker : IAsyncDisposable
         _testOut = testOut;
     }
 
+    // Convenience properties.
+    public RobustIntegrationTest.ServerIntegrationInstance Server => Pair.Server;
+    public RobustIntegrationTest.ClientIntegrationInstance Client => Pair.Client;
+
     private async Task OnDirtyDispose()
     {
         var usageTime = UsageWatch.Elapsed;
@@ -957,6 +961,10 @@ public sealed class PairTracker : IAsyncDisposable
         PoolManager.NoCheckReturn(Pair);
         var disposeTime = dirtyWatch.Elapsed;
         await _testOut.WriteLineAsync($"{nameof(DisposeAsync)}: Disposed pair {Pair.PairId} in {disposeTime.TotalMilliseconds} ms");
+
+        // Test pairs should only dirty dispose if they are failing. If they are not failing, this probably happened
+        // because someone forgot to clean-return the pair.
+        Assert.Warn("Test was dirty-disposed.");
     }
 
     private async Task OnCleanDispose()