feat(audit): redactor + writer helpers (Null/Truncating/NoOp/Composite/Redacting)

Code-review fixes: CompositeAuditWriter re-throws OperationCanceledException (honors cancellation) + evt null-guard; RedactingAuditWriter evt null-guard; added marker-longer-than-max and cancellation-propagation regression tests.
2026-06-01 07:28:13 -04:00
parent 3934e528f2
commit 453ec7358d
11 changed files with 283 additions and 0 deletions
@@ -0,0 +1,48 @@
+namespace ZB.MOM.WW.Audit.Tests;
+
+public class CompositeAuditWriterTests
+{
+    private sealed class RecordingWriter : IAuditWriter
+    {
+        public int Count;
+        public Task WriteAsync(AuditEvent evt, CancellationToken ct = default) { Count++; return Task.CompletedTask; }
+    }
+    private sealed class ThrowingWriter : IAuditWriter
+    {
+        public Task WriteAsync(AuditEvent evt, CancellationToken ct = default) => throw new InvalidOperationException("boom");
+    }
+    private sealed class CancellingWriter : IAuditWriter
+    {
+        public Task WriteAsync(AuditEvent evt, CancellationToken ct = default) => throw new OperationCanceledException();
+    }
+
+    private static AuditEvent Evt() => new() { EventId = Guid.NewGuid(), OccurredAtUtc = DateTimeOffset.UtcNow,
+        Actor = "a", Action = "x", Outcome = AuditOutcome.Success };
+
+    [Fact]
+    public async Task Fans_out_to_all_writers()
+    {
+        var a = new RecordingWriter(); var b = new RecordingWriter();
+        await new CompositeAuditWriter(new IAuditWriter[] { a, b }).WriteAsync(Evt());
+        Assert.Equal(1, a.Count);
+        Assert.Equal(1, b.Count);
+    }
+
+    [Fact]
+    public async Task One_failing_writer_does_not_stop_the_others()
+    {
+        var after = new RecordingWriter();
+        var sut = new CompositeAuditWriter(new IAuditWriter[] { new ThrowingWriter(), after });
+        await sut.WriteAsync(Evt()); // must not throw
+        Assert.Equal(1, after.Count);
+    }
+
+    [Fact]
+    public async Task Cancellation_is_propagated_not_swallowed()
+    {
+        // OperationCanceledException is re-thrown (unlike ordinary writer failures, which are swallowed).
+        var after = new RecordingWriter();
+        var sut = new CompositeAuditWriter(new IAuditWriter[] { new CancellingWriter(), after });
+        await Assert.ThrowsAsync<OperationCanceledException>(() => sut.WriteAsync(Evt()));
+    }
+}
@@ -0,0 +1,12 @@
+namespace ZB.MOM.WW.Audit.Tests;
+
+public class NoOpAuditWriterTests
+{
+    [Fact]
+    public async Task WriteAsync_completes_without_error()
+    {
+        var evt = new AuditEvent { EventId = Guid.NewGuid(), OccurredAtUtc = DateTimeOffset.UtcNow,
+            Actor = "a", Action = "x", Outcome = AuditOutcome.Success };
+        await NoOpAuditWriter.Instance.WriteAsync(evt);
+    }
+}
@@ -0,0 +1,12 @@
+namespace ZB.MOM.WW.Audit.Tests;
+
+public class NullAuditRedactorTests
+{
+    [Fact]
+    public void Apply_returns_input_unchanged()
+    {
+        var evt = new AuditEvent { EventId = Guid.NewGuid(), OccurredAtUtc = DateTimeOffset.UtcNow,
+            Actor = "a", Action = "x", Outcome = AuditOutcome.Success, DetailsJson = "{\"k\":1}" };
+        Assert.Same(evt, NullAuditRedactor.Instance.Apply(evt));
+    }
+}
@@ -0,0 +1,26 @@
+namespace ZB.MOM.WW.Audit.Tests;
+
+public class RedactingAuditWriterTests
+{
+    private sealed class CapturingWriter : IAuditWriter
+    {
+        public AuditEvent? Last;
+        public Task WriteAsync(AuditEvent evt, CancellationToken ct = default) { Last = evt; return Task.CompletedTask; }
+    }
+    private sealed class StampRedactor : IAuditRedactor
+    {
+        public AuditEvent Apply(AuditEvent rawEvent) => rawEvent with { DetailsJson = "redacted" };
+    }
+
+    private static AuditEvent Evt() => new() { EventId = Guid.NewGuid(), OccurredAtUtc = DateTimeOffset.UtcNow,
+        Actor = "a", Action = "x", Outcome = AuditOutcome.Success, DetailsJson = "secret" };
+
+    [Fact]
+    public async Task Inner_writer_receives_the_redacted_event()
+    {
+        var inner = new CapturingWriter();
+        var sut = new RedactingAuditWriter(new StampRedactor(), inner);
+        await sut.WriteAsync(Evt());
+        Assert.Equal("redacted", inner.Last!.DetailsJson);
+    }
+}
@@ -0,0 +1,56 @@
+namespace ZB.MOM.WW.Audit.Tests;
+
+public class TruncatingAuditRedactorTests
+{
+    private static AuditEvent Evt(string? details, string? target = null) => new()
+    {
+        EventId = Guid.NewGuid(), OccurredAtUtc = DateTimeOffset.UtcNow,
+        Actor = "a", Action = "x", Outcome = AuditOutcome.Success,
+        DetailsJson = details, Target = target,
+    };
+
+    [Fact]
+    public void Short_values_pass_through_unchanged()
+    {
+        var r = new TruncatingAuditRedactor(new() { MaxDetailsJsonLength = 100 });
+        var evt = Evt("small");
+        Assert.Equal("small", r.Apply(evt).DetailsJson);
+    }
+
+    [Fact]
+    public void Oversized_details_are_truncated_with_marker()
+    {
+        var opts = new TruncatingAuditRedactorOptions { MaxDetailsJsonLength = 10, TruncationMarker = "~" };
+        var r = new TruncatingAuditRedactor(opts);
+        var result = r.Apply(Evt(new string('x', 50)));
+        Assert.Equal(10, result.DetailsJson!.Length);
+        Assert.EndsWith("~", result.DetailsJson);
+    }
+
+    [Fact]
+    public void Oversized_target_is_truncated()
+    {
+        var r = new TruncatingAuditRedactor(new() { MaxTargetLength = 5, TruncationMarker = "" });
+        var result = r.Apply(Evt(null, target: "abcdefghij"));
+        Assert.Equal(5, result.Target!.Length);
+    }
+
+    [Fact]
+    public void Null_fields_are_left_null()
+    {
+        var r = new TruncatingAuditRedactor();
+        var result = r.Apply(Evt(null));
+        Assert.Null(result.DetailsJson);
+        Assert.Null(result.Target);
+    }
+
+    [Fact]
+    public void Marker_longer_than_max_clips_the_marker_itself()
+    {
+        // Misconfiguration: marker longer than the cap. Must not throw; clips to the first max chars.
+        var opts = new TruncatingAuditRedactorOptions { MaxDetailsJsonLength = 3, TruncationMarker = "…[truncated]" };
+        var r = new TruncatingAuditRedactor(opts);
+        var result = r.Apply(Evt(new string('x', 20)));
+        Assert.Equal(3, result.DetailsJson!.Length);
+    }
+}