Harden speaker identity samples

MeetingAssistant.Tests/AzureSpeechSpeakerIdentityMatcherTests.cs

@@ -118,9 +118,33 @@ public sealed class AzureSpeechSpeakerIdentityMatcherTests
         Assert.Null(match);
     }
 
+    [Fact]
+    public async Task MatcherReturnsNullWhenSecondaryValidatorRejectsPrimaryMatch()
+    {
+        var diarizationClient = new FakeSpeakerIdentityDiarizationClient(
+        [
+            new TranscriptionSegment(TimeSpan.Zero, TimeSpan.FromSeconds(1), "Guest-1", "known"),
+            new TranscriptionSegment(TimeSpan.FromSeconds(2), TimeSpan.FromSeconds(3), "Guest-1", "unknown")
+        ]);
+        var validator = new RejectingSpeakerIdentityMatchValidator();
+        var matcher = CreateMatcher(diarizationClient, validator: validator);
+        var snippet = CreateWavSnippet();
+
+        var match = await matcher.MatchAsync(
+            new SpeakerIdentityMatchRequest(
+                "Guest03",
+                snippet,
+                [new SpeakerIdentityMatchCandidate(42, "Chris", 5, [snippet])]),
+            CancellationToken.None);
+
+        Assert.Null(match);
+        Assert.Equal(1, validator.MatchValidationCount);
+    }
+
     private static AzureSpeechSpeakerIdentityMatcher CreateMatcher(
         ISpeakerIdentityDiarizationClient diarizationClient,
-        TimeSpan? matchTimeout = null)
+        TimeSpan? matchTimeout = null,
+        ISpeakerIdentityMatchValidator? validator = null)
     {
         return new AzureSpeechSpeakerIdentityMatcher(
             diarizationClient,
@@ -132,7 +156,8 @@ public sealed class AzureSpeechSpeakerIdentityMatcherTests
                     MatchTimeout = matchTimeout ?? TimeSpan.FromMinutes(1)
                 }
             }),
-            NullLogger<AzureSpeechSpeakerIdentityMatcher>.Instance);
+            NullLogger<AzureSpeechSpeakerIdentityMatcher>.Instance,
+            validator ?? new NoopSpeakerIdentityMatchValidator());
     }
 
     private static byte[] CreateWavSnippet()
@@ -177,4 +202,22 @@ public sealed class AzureSpeechSpeakerIdentityMatcherTests
             return [];
         }
     }
+
+    private sealed class RejectingSpeakerIdentityMatchValidator : ISpeakerIdentityMatchValidator
+    {
+        public int MatchValidationCount { get; private set; }
+
+        public Task<bool> ValidateSampleAsync(byte[] wavBytes, CancellationToken cancellationToken)
+        {
+            return Task.FromResult(true);
+        }
+
+        public Task<bool> ValidateMatchAsync(
+            SpeakerIdentityMatchValidationRequest request,
+            CancellationToken cancellationToken)
+        {
+            MatchValidationCount++;
+            return Task.FromResult(false);
+        }
+    }
 }