Add inactivity safeguard and speaker diagnostics

MeetingAssistant.Tests/SpeakerIdentityServiceTests.cs

@@ -3,6 +3,7 @@ using MeetingAssistant.MeetingNotes;
 using MeetingAssistant.Speakers;
 using MeetingAssistant.Transcription;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 
@@ -149,6 +150,28 @@ public sealed class SpeakerIdentityServiceTests
         });
     }
 
+    [Fact]
+    public async Task RejectedUnmatchedSpeakerSampleIsLoggedWithSpeakerAndCandidateContext()
+    {
+        await using var fixture = await SpeakerIdentityFixture.CreateAsync();
+        fixture.MatchValidator.SampleIsValid = false;
+        var logger = new CapturingLogger<SpeakerIdentityService>();
+        var service = fixture.CreateService(logger);
+
+        await service.ProcessFinishedTranscriptAsync(
+            fixture.CreateRequest(
+                ["John", "Mike"],
+                [new TranscriptionSegment(TimeSpan.Zero, TimeSpan.FromSeconds(4), "Guest01", "unknown speaker")]),
+            CancellationToken.None);
+
+        var message = Assert.Single(
+            logger.Messages,
+            message => message.Contains("Skipping speaker identity candidate for Guest01", StringComparison.Ordinal));
+        Assert.Contains("Skipping speaker identity candidate for Guest01", message);
+        Assert.Contains("candidate names John, Mike", message);
+        Assert.Contains("sample bytes 3", message);
+    }
+
     [Fact]
     public async Task UnmatchedSpeakersExcludeAliasesOfMatchedIdentitiesFromCandidates()
     {
@@ -648,14 +671,14 @@ public sealed class SpeakerIdentityServiceTests
             return new SpeakerIdentityFixture(tempDirectory, dbPath, context, options);
         }
 
-        public SpeakerIdentityService CreateService()
+        public SpeakerIdentityService CreateService(ILogger<SpeakerIdentityService>? logger = null)
         {
             return new SpeakerIdentityService(
                 new TestSpeakerIdentityDbContextFactory(dbPath),
                 SnippetExtractor,
                 Matcher,
                 Options.Create(new MeetingAssistantOptions { SpeakerIdentification = options }),
-                NullLogger<SpeakerIdentityService>.Instance,
+                logger ?? NullLogger<SpeakerIdentityService>.Instance,
                 MatchValidator);
         }
 
@@ -836,4 +859,30 @@ public sealed class SpeakerIdentityServiceTests
             return Task.FromResult(true);
         }
     }
+
+    private sealed class CapturingLogger<T> : ILogger<T>
+    {
+        public List<string> Messages { get; } = [];
+
+        public IDisposable? BeginScope<TState>(TState state)
+            where TState : notnull
+        {
+            return null;
+        }
+
+        public bool IsEnabled(LogLevel logLevel)
+        {
+            return true;
+        }
+
+        public void Log<TState>(
+            LogLevel logLevel,
+            EventId eventId,
+            TState state,
+            Exception? exception,
+            Func<TState, Exception?, string> formatter)
+        {
+            Messages.Add(formatter(state, exception));
+        }
+    }
 }