more audit work

src/__Libraries/__Tests/StellaOps.Signals.Tests/AGENTS.md

@@ -0,0 +1,29 @@
+# StellaOps.Signals.Tests - Local Agent Charter
+
+## Roles
+- Backend developer
+- QA automation engineer
+
+## Working directory
+- src/__Libraries/__Tests/StellaOps.Signals.Tests
+
+## Allowed dependencies
+- src/Signals/StellaOps.Signals
+- src/__Libraries/StellaOps.TestKit
+
+## Required reading
+- docs/README.md
+- docs/07_HIGH_LEVEL_ARCHITECTURE.md
+- docs/modules/platform/architecture-overview.md
+- docs/modules/signals/README.md
+- docs/modules/signals/contracts/signals-provenance-contract.md
+
+## Determinism and test rules
+- Use deterministic inputs; avoid DateTime.UtcNow, DateTimeOffset.UtcNow, Guid.NewGuid, and Random.Shared in tests.
+- Use TimeProvider and fixed seeds or fixtures for time- and randomness-dependent tests.
+- Use CultureInfo.InvariantCulture for parsing and formatting in tests.
+- Tag tests with TestCategories (Unit, Integration, Performance) and keep integration tests out of unit-only runs.
+
+## Quality and safety
+- ASCII-only strings and comments unless explicitly justified.
+- Keep fixtures small and deterministic; clean up temp resources.

src/__Libraries/__Tests/StellaOps.Signals.Tests/TASKS.md

@@ -0,0 +1,10 @@
+# StellaOps.Signals.Tests Task Board
+
+This board mirrors active sprint tasks for this module.
+Source of truth: `docs/implplan/SPRINT_20251229_049_BE_csproj_audit_maint_tests.md`.
+
+| Task ID | Status | Notes |
+| --- | --- | --- |
+| AUDIT-0037-M | DONE | Revalidated 2026-01-08; open findings tracked in audit report. |
+| AUDIT-0037-T | DONE | Revalidated 2026-01-08; open findings tracked in audit report. |
+| AUDIT-0037-A | DONE | Waived (test project; revalidated 2026-01-08). |

src/__Libraries/__Tests/StellaOps.Signals.Tests/TestInfrastructure/InMemoryReachabilityCache.cs

@@ -0,0 +1,32 @@
+using System.Collections.Concurrent;
+using System.Threading;
+using System.Threading.Tasks;
+using StellaOps.Signals.Models;
+using StellaOps.Signals.Services;
+
+namespace StellaOps.Signals.Tests.TestInfrastructure;
+
+internal sealed class InMemoryReachabilityCache : IReachabilityCache
+{
+    private readonly ConcurrentDictionary<string, ReachabilityFactDocument> cache = new(StringComparer.Ordinal);
+
+    public Task<ReachabilityFactDocument?> GetAsync(string subjectKey, CancellationToken cancellationToken)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return Task.FromResult(cache.TryGetValue(subjectKey, out var document) ? document : null);
+    }
+
+    public Task SetAsync(ReachabilityFactDocument document, CancellationToken cancellationToken)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        cache[document.SubjectKey] = document;
+        return Task.CompletedTask;
+    }
+
+    public Task InvalidateAsync(string subjectKey, CancellationToken cancellationToken)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        cache.TryRemove(subjectKey, out _);
+        return Task.CompletedTask;
+    }
+}

src/__Libraries/__Tests/StellaOps.Signals.Tests/TestInfrastructure/SignalsTestFactory.cs

@@ -5,6 +5,9 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc.Testing;
 using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using StellaOps.Signals.Services;
 
 namespace StellaOps.Signals.Tests.TestInfrastructure;
 
@@ -33,6 +36,12 @@ public sealed class SignalsTestFactory : WebApplicationFactory<Program>, IAsyncL
 
             configuration.AddInMemoryCollection(settings);
         });
+
+        builder.ConfigureServices(services =>
+        {
+            services.RemoveAll<IReachabilityCache>();
+            services.AddSingleton<IReachabilityCache, InMemoryReachabilityCache>();
+        });
     }
 
     public ValueTask InitializeAsync() => ValueTask.CompletedTask;