(#171) Get logs with predicate

Author: colinangusmackay

src/Stravaig.Extensions.Logging.Diagnostics.Tests/TestCaptureLoggerOfTTests.cs

@@ -8,6 +8,21 @@ namespace Stravaig.Extensions.Logging.Diagnostics.Tests;
 [TestFixture]
 public class TestCaptureLoggerOfTTests
 {
+    [Test]
+    public void ConstructorWithNullLoggerThrows()
+    {
+        Should.Throw<ArgumentNullException>(() => new TestCaptureLogger<object>(null!))
+            .ParamName.ShouldBe("logger");
+    }
+
+    [Test]
+    public void ConstructorCategoryMismatchThrows()
+    {
+        var underlyingLogger = new TestCaptureLogger("NotTheRightCategory");
+        Should.Throw<InvalidOperationException>(() => new TestCaptureLogger<object>(underlyingLogger))
+            .Message.ShouldBe("The category name does not match the type of this logger. Expected \"object\", got \"NotTheRightCategory\".");
+    }
+
     [Test]
     public void CategoryNameIsBasedOnType()
     {
@@ -52,4 +67,20 @@ public void GetLogsWithExceptionsWillFilterOutNonExceptionLogs()
         logger.GetLogEntriesWithExceptions().Count.ShouldBe(2);
         logger.GetLogs().Count.ShouldBe(4);
     }
+
+    [Test]
+    public void GetLogsMatchingPredicateWillFilterOutUnwantedLogs()
+    {
+        var logger = new TestCaptureLogger<TestCaptureLoggerOfTTests>();
+        logger.LogInformation("Hello");
+        logger.LogWarning("Hello, {Location}!", "World");
+        logger.LogInformation("This is a log.");
+        logger.LogError(new Exception(), "This has an exception.");
+
+        logger.GetLogs(static l => l.LogLevel == LogLevel.Information).Count.ShouldBe(2);
+
+        logger.GetLogs(static l => l.PropertyDictionary.ContainsKey("Location") && (string)l.PropertyDictionary["Location"] == "World")
+            .Count.ShouldBe(1);
+        logger.GetLogs().Count.ShouldBe(4);
+    }
 }

src/Stravaig.Extensions.Logging.Diagnostics/ITestCaptureLogger.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using Microsoft.Extensions.Logging;
 
@@ -20,6 +21,13 @@ public interface ITestCaptureLogger : ILogger
     /// called won't be available in the list, and it will have to be called again.</remarks>
     IReadOnlyList<LogEntry> GetLogs();
 
+    /// <summary>
+    /// Gets a read-only list of logs that is a snapshot of this logger filtered by the predicate.
+    /// </summary>
+    /// <remarks>Any additional logs added to the logger after this is
+    /// called won't be available in the list, and it will have to be called again.</remarks>
+    IReadOnlyList<LogEntry> GetLogs(Func<LogEntry, bool> predicate);
+
     /// <summary>
     /// Gets a read-only list of logs that have an exception attached in sequential order.
     /// </summary>

src/Stravaig.Extensions.Logging.Diagnostics/TestCaptureLogger(OfTCategoryType).cs

@@ -28,6 +28,7 @@ public TestCaptureLogger()
     /// </summary>
     public TestCaptureLogger(TestCaptureLogger logger)
     {
+        ArgumentNullException.ThrowIfNull(logger, nameof(logger));
         var expectedCategoryName = TypeNameHelper.GetTypeDisplayName(typeof(TCategoryType));
         if (logger.CategoryName != expectedCategoryName)
             throw new InvalidOperationException(
@@ -66,6 +67,10 @@ public void Reset()
     public IReadOnlyList<LogEntry> GetLogs()
         => _logger.GetLogs();
 
+    /// <inheritdoc />
+    public IReadOnlyList<LogEntry> GetLogs(Func<LogEntry, bool> predicate)
+        => _logger.GetLogs(predicate);
+
     /// <summary>
     /// Gets a read-only list of logs that have an exception attached in sequential order.
     /// </summary>

src/Stravaig.Extensions.Logging.Diagnostics/TestCaptureLogger.cs

@@ -49,21 +49,23 @@ public IReadOnlyList<LogEntry> GetLogs()
         }
     }
 
-
     /// <inheritdoc />
-    public IReadOnlyList<LogEntry> GetLogEntriesWithExceptions()
+    public IReadOnlyList<LogEntry> GetLogs(Func<LogEntry, bool> predicate)
     {
-        List<LogEntry> result;
         lock (_syncRoot)
         {
-            result = _logs
-                .Where(l => l.Exception != null)
-                .ToList();
+            return _logs
+                .Where(predicate)
+                .OrderBy(static log => log)
+                .ToArray();
         }
-        result.Sort();
-        return result;
     }
 
+
+    /// <inheritdoc />
+    public IReadOnlyList<LogEntry> GetLogEntriesWithExceptions()
+        => GetLogs(log => log.Exception != null);
+
     /// <summary>
     /// Writes a log entry
     /// </summary>

src/Stravaig.Extensions.Logging.Diagnostics/TestCaptureLoggerProvider.cs

@@ -103,18 +103,27 @@ public IReadOnlyList<LogEntry> GetAllLogEntries()
     }
 
     /// <summary>
-    /// Gets all log entries with exceptions attached regardless of the
-    /// Category they were logged as.
+    /// Gets all log entries matching the predicate regardless of the Category
+    /// they were logged as.
     /// </summary>
-    /// <returns>A read only list of <see cref="LogEntry"/></returns>
-    public IReadOnlyList<LogEntry> GetAllLogEntriesWithExceptions()
+    /// <returns>A read only list of <see cref="LogEntry"/> objects.</returns>
+    public IReadOnlyList<LogEntry> GetLogEntriesMatchingPredicate(Func<LogEntry, bool> predicate)
     {
         var loggers = _captures.Values;
-        var allLogs = loggers.SelectMany(l => l.GetLogEntriesWithExceptions()).ToList();
+        var allLogs = loggers.SelectMany(l => l.GetLogs(predicate)).ToList();
         allLogs.Sort();
         return allLogs;
     }
 
+
+    /// <summary>
+    /// Gets all log entries with exceptions attached regardless of the
+    /// Category they were logged as.
+    /// </summary>
+    /// <returns>A read only list of <see cref="LogEntry"/> objects.</returns>
+    public IReadOnlyList<LogEntry> GetAllLogEntriesWithExceptions()
+        => GetLogEntriesMatchingPredicate(static log => log.Exception != null);
+
     /// <summary>
     /// Resets the captures to an empty state.
     /// </summary>