Improve meaningful core coverage and enforce its floor

.github/workflows/ci-devsecops.yml

@@ -55,8 +55,8 @@ jobs:
           [xml]$coverage = Get-Content $coveragePath
           $lineRate = [double]$coverage.coverage.'line-rate' * 100
           $branchRate = [double]$coverage.coverage.'branch-rate' * 100
-          # Temporary floor until the service-hardening coverage tasks land.
-          $minimumLineRate = 1.5
+          # Keep the gate slightly below measured main coverage so meaningful tests can raise it deliberately.
+          $minimumLineRate = 35.0
 
           $summary = @(
             "## Coverage Gate",

Services/LogFileManager.cs

@@ -109,12 +109,11 @@ public async Task<List<string>> ReadLogEntriesAsync(DateTime fromDate, DateTime
 
         public async Task<LogFileStatistics> GetStatisticsAsync()
         {
+            var stats = new LogFileStatistics();
             await this.fileLock.WaitAsync();
             try
             {
-                var stats = new LogFileStatistics();
                 var logFiles = this.GetLogFiles();
-
                 stats.TotalLogFiles = logFiles.Count;
 
                 foreach (var logFile in logFiles)
@@ -137,16 +136,14 @@ public async Task<LogFileStatistics> GetStatisticsAsync()
                         stats.NewestLogDate = fileInfo.CreationTime;
                     }
                 }
-
-                // Count log levels by reading recent entries
-                await this.CountLogLevelsAsync(stats);
-
-                return stats;
             }
             finally
             {
                 this.fileLock.Release();
             }
+
+            await this.CountLogLevelsAsync(stats);
+            return stats;
         }
 
         public async Task CleanupOldLogsAsync()

Tests/ThreadPilot.Core.Tests/LogFileManagerTests.cs

@@ -0,0 +1,123 @@
+namespace ThreadPilot.Core.Tests
+{
+    using Microsoft.Extensions.Logging.Abstractions;
+    using ThreadPilot.Services;
+
+    public sealed class LogFileManagerTests
+    {
+        [Fact]
+        public async Task WriteReadStatisticsAndExport_RoundTripStructuredEntries()
+        {
+            var directory = CreateTemporaryDirectory();
+            var exportPath = Path.Combine(directory, "export.txt");
+            using var manager = new LogFileManager(NullLogger<LogFileManager>.Instance, directory);
+            var now = DateTime.UtcNow;
+            var information = CreateEntry(now.AddMinutes(-2), "Information", "started");
+            var warning = CreateEntry(now.AddMinutes(-1), "Warning", "warning");
+            var error = CreateEntry(now, "Error", "failed");
+
+            try
+            {
+                await manager.InitializeAsync();
+                await manager.WriteLogEntriesAsync([information, "not-json", warning]);
+                await manager.WriteLogEntryAsync(error);
+
+                var entries = await manager.ReadLogEntriesAsync(now.AddMinutes(-3), now.AddMinutes(1), maxEntries: 2);
+                var statistics = await manager.GetStatisticsAsync();
+                var resultPath = await manager.ExportLogsAsync(now.AddMinutes(-3), now.AddMinutes(1), exportPath);
+
+                Assert.Equal([error, warning], entries);
+                Assert.Equal(1, statistics.TotalLogFiles);
+                Assert.Equal(1, statistics.InfoCount);
+                Assert.Equal(1, statistics.WarningCount);
+                Assert.Equal(1, statistics.ErrorCount);
+                Assert.True(statistics.CurrentFileSizeBytes > 0);
+                Assert.Equal(exportPath, resultPath);
+                var export = await File.ReadAllTextAsync(exportPath);
+                Assert.Contains("# Total Entries: 3", export, StringComparison.Ordinal);
+                Assert.Contains(information, export, StringComparison.Ordinal);
+                Assert.DoesNotContain("not-json", export, StringComparison.Ordinal);
+            }
+            finally
+            {
+                DeleteDirectory(directory);
+            }
+        }
+
+        [Fact]
+        public async Task WriteLogEntry_WhenSizeLimitExceeded_RotatesAndKeepsCurrentLog()
+        {
+            var directory = CreateTemporaryDirectory();
+            using var manager = new LogFileManager(NullLogger<LogFileManager>.Instance, directory);
+
+            try
+            {
+                await manager.InitializeAsync();
+                manager.UpdateConfiguration(maxFileSizeMb: 0, retentionDays: 7);
+
+                await manager.WriteLogEntryAsync(CreateEntry(DateTime.UtcNow, "Information", "after rotation"));
+
+                var files = Directory.GetFiles(directory, "*.log");
+                Assert.Equal(2, files.Length);
+                Assert.Contains(files, path => Path.GetFileName(path) == "ThreadPilot.log");
+                Assert.Contains(files, path => Path.GetFileName(path).StartsWith("ThreadPilot_", StringComparison.Ordinal));
+                Assert.Contains("after rotation", await File.ReadAllTextAsync(manager.CurrentLogFilePath), StringComparison.Ordinal);
+            }
+            finally
+            {
+                DeleteDirectory(directory);
+            }
+        }
+
+        [Fact]
+        public async Task CleanupOldLogs_RemovesExpiredAndExcessFilesButKeepsCurrentLog()
+        {
+            var directory = CreateTemporaryDirectory();
+            using var manager = new LogFileManager(NullLogger<LogFileManager>.Instance, directory);
+
+            try
+            {
+                await manager.InitializeAsync();
+                var expired = Path.Combine(directory, "ThreadPilot_expired.log");
+                var older = Path.Combine(directory, "ThreadPilot_older.log");
+                var newer = Path.Combine(directory, "ThreadPilot_newer.log");
+                await File.WriteAllTextAsync(expired, "expired");
+                await File.WriteAllTextAsync(older, "older");
+                await File.WriteAllTextAsync(newer, "newer");
+                File.SetCreationTimeUtc(expired, DateTime.UtcNow.AddDays(-10));
+                File.SetCreationTimeUtc(older, DateTime.UtcNow.AddHours(-2));
+                File.SetCreationTimeUtc(newer, DateTime.UtcNow.AddHours(-1));
+                manager.UpdateConfiguration(maxFileSizeMb: 10, retentionDays: 2, maxLogFiles: 1);
+
+                await manager.CleanupOldLogsAsync();
+
+                Assert.True(File.Exists(manager.CurrentLogFilePath));
+                Assert.False(File.Exists(expired));
+                Assert.False(File.Exists(older));
+                Assert.True(File.Exists(newer));
+            }
+            finally
+            {
+                DeleteDirectory(directory);
+            }
+        }
+
+        private static string CreateEntry(DateTime timestamp, string level, string message) =>
+            $"{{\"timestamp\":\"{timestamp:yyyy-MM-dd HH:mm:ss.fff}\",\"level\":\"{level}\",\"message\":\"{message}\"}}";
+
+        private static string CreateTemporaryDirectory()
+        {
+            var directory = Path.Combine(Path.GetTempPath(), $"threadpilot-log-manager-{Guid.NewGuid():N}");
+            Directory.CreateDirectory(directory);
+            return directory;
+        }
+
+        private static void DeleteDirectory(string directory)
+        {
+            if (Directory.Exists(directory))
+            {
+                Directory.Delete(directory, recursive: true);
+            }
+        }
+    }
+}