more audit work

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

@@ -0,0 +1,23 @@
+# Hybrid Logical Clock Tests Charter
+
+## Mission
+Validate HLC timestamping, serialization, and monotonic behavior across scenarios.
+
+## Responsibilities
+- Maintain unit/integration tests for HLC behavior and state stores.
+- Keep tests deterministic and offline-friendly.
+- Track sprint tasks in `TASKS.md` and update the sprint tracker.
+
+## Key Paths
+- `HlcTimestampTests.cs`
+- `HybridLogicalClockTests.cs`
+- `HybridLogicalClockIntegrationTests.cs`
+
+## Required Reading
+- `docs/modules/platform/architecture-overview.md`
+- `docs/implplan/permament/SPRINT_20251229_049_BE_csproj_audit_maint_tests.md`
+
+## Working Agreement
+- 1. Avoid hardware-dependent perf assertions in CI by gating as needed.
+- 2. Use deterministic TimeProvider in tests.
+- 3. Update `TASKS.md` and sprint statuses when work changes.

src/__Libraries/__Tests/StellaOps.HybridLogicalClock.Tests/HlcTimestampTests.cs

@@ -98,9 +98,9 @@ public class HlcTimestampTests
     }
 
     [Fact]
-    public void Parse_NullString_ThrowsArgumentException()
+    public void Parse_NullString_ThrowsArgumentNullException()
     {
-        Assert.Throws<ArgumentException>(() => HlcTimestamp.Parse(null!));
+        Assert.Throws<ArgumentNullException>(() => HlcTimestamp.Parse(null!));
     }
 
     [Fact]
@@ -457,9 +457,9 @@ public class HlcTimestampTests
     }
 
     [Fact]
-    public void Now_NullNodeId_ThrowsArgumentException()
+    public void Now_NullNodeId_ThrowsArgumentNullException()
     {
-        Assert.Throws<ArgumentException>(() => HlcTimestamp.Now(null!, TimeProvider.System));
+        Assert.Throws<ArgumentNullException>(() => HlcTimestamp.Now(null!, TimeProvider.System));
     }
 
     [Fact]

src/__Libraries/__Tests/StellaOps.HybridLogicalClock.Tests/HybridLogicalClockTests.cs

@@ -431,9 +431,9 @@ public class HybridLogicalClockTests
     }
 
     [Fact]
-    public void Constructor_NullNodeId_ThrowsArgumentException()
+    public void Constructor_NullNodeId_ThrowsArgumentNullException()
     {
-        Assert.Throws<ArgumentException>(() =>
+        Assert.Throws<ArgumentNullException>(() =>
             new HybridLogicalClock(
                 TimeProvider.System,
                 null!,

src/__Libraries/__Tests/StellaOps.HybridLogicalClock.Tests/InMemoryHlcStateStoreTests.cs

@@ -68,11 +68,11 @@ public class InMemoryHlcStateStoreTests
     }
 
     [Fact]
-    public async Task LoadAsync_NullNodeId_ThrowsArgumentException()
+    public async Task LoadAsync_NullNodeId_ThrowsArgumentNullException()
     {
         var store = new InMemoryHlcStateStore();
 
-        await Assert.ThrowsAsync<ArgumentException>(() => store.LoadAsync(null!));
+        await Assert.ThrowsAsync<ArgumentNullException>(() => store.LoadAsync(null!));
     }
 
     [Fact]

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

@@ -0,0 +1,10 @@
+# Hybrid Logical Clock Tests Task Board
+
+This board mirrors active sprint tasks for this module.
+Source of truth: `docs/implplan/permament/SPRINT_20251229_049_BE_csproj_audit_maint_tests.md`.
+
+| Task ID | Status | Notes |
+| --- | --- | --- |
+| AUDIT-0027-M | DONE | Revalidated 2026-01-08; open findings tracked in audit report. |
+| AUDIT-0027-T | DONE | Revalidated 2026-01-08; open findings tracked in audit report. |
+| AUDIT-0027-A | DONE | Waived (test project; revalidated 2026-01-08). |