Fix normalizer sidecar log and coverage test (#4)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/Recordingtest.Normalizer.Tests/RuleTests.cs

@@ -67,12 +67,62 @@ public class RuleTests
     {
         var input = "{\"ts\":\"2026-04-07T00:00:00Z\",\"x\":1.23456789}";
         var r = Normalizer.Normalize(input, "default");
-        Assert.Equal(5, r.Log.Count);
+        Assert.Equal(6, r.Log.Count);
         var ids = r.Log.Select(l => l.RuleId).ToList();
         Assert.Contains("strip_timestamps", ids);
         Assert.Contains("mask_guids", ids);
         Assert.Contains("normalize_paths", ids);
         Assert.Contains("round_floats", ids);
         Assert.Contains("sort_json_keys", ids);
+        Assert.Contains("mask_volatile_settings", ids);
+    }
+
+    [Fact]
+    public void Normalize_WritesSidecarLogFile()
+    {
+        var input = "{\"ts\":\"2026-04-07T00:00:00Z\",\"id\":\"550e8400-e29b-41d4-a716-446655440000\",\"GridSnap\":true,\"x\":1.234567}";
+        var tmp = Path.Combine(Path.GetTempPath(), "norm-sidecar-" + Guid.NewGuid().ToString("N") + ".log");
+        try
+        {
+            var r = Normalizer.Normalize(input, "default", tmp);
+            Assert.True(File.Exists(tmp), "sidecar file should exist at " + tmp);
+            var text = File.ReadAllText(tmp);
+
+            // every rule from result.Log should appear with matching count
+            int total = 0;
+            foreach (var entry in r.Log)
+            {
+                Assert.Contains($"{entry.RuleId}\tcount={entry.Count}", text);
+                total += entry.Count;
+            }
+            Assert.Contains($"total={total}", text);
+
+            // sorted by RuleId
+            var lines = text.Split('\n', StringSplitOptions.RemoveEmptyEntries);
+            var ruleLines = lines.Where(l => !l.StartsWith("total=")).ToList();
+            var sorted = ruleLines.OrderBy(l => l, StringComparer.Ordinal).ToList();
+            Assert.Equal(sorted, ruleLines);
+        }
+        finally
+        {
+            if (File.Exists(tmp)) File.Delete(tmp);
+        }
+    }
+
+    [Fact]
+    public void Normalize_SidecarPath_AcceptsDirectory()
+    {
+        var dir = Path.Combine(Path.GetTempPath(), "norm-sidecar-dir-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(dir);
+        try
+        {
+            Normalizer.Normalize("{\"a\":1}", "default", dir);
+            var expected = Path.Combine(dir, "normalization.log");
+            Assert.True(File.Exists(expected));
+        }
+        finally
+        {
+            if (Directory.Exists(dir)) Directory.Delete(dir, true);
+        }
     }
 }