Fixed bug where MergedLogFile would scramble the order of lines with …

…identical timestamps compared to their original order

This occured due to the re-write sorting indices (using an unstable sort) before inserting them => Replaced with stable sort #154

src/Tailviewer.AcceptanceTests/BusinessLogic/LogFiles/MergedLogFileTest.cs

@@ -1,8 +1,6 @@
 using System;
-using System.IO;
 using System.Threading;
 using FluentAssertions;
-using log4net.Core;
 using NUnit.Framework;
 using Tailviewer.BusinessLogic;
 using Tailviewer.BusinessLogic.LogFiles;

src/Tailviewer.Core/LogFiles/Merged/MergedLogFileIndex.cs

@@ -472,9 +472,8 @@ private IReadOnlyList<MergedLogLineIndex> CreateIndices(
 				indices.AddRange(CreateIndices(entries, logFileIndex));
 			}
 
-			indices.Sort(new MergedLogLineIndexComparer());
-
-			return indices;
+			// TODO: Create unit test which fails if we don't use a stable sort...
+			return indices.OrderBy(x => x.Timestamp).ToList();
 		}
 
 		[Pure]

src/Tailviewer.Test/BusinessLogic/LogFiles/Merged/MergedLogFileIndexTest.cs

@@ -328,6 +328,33 @@ public void TestOneSourceResetAndAppend()
 			index.Count.Should().Be(1);
 		}
 
+		[Test]
+		public void TestOneSourceManySameTimestamps()
+		{
+			var source = new InMemoryLogFile();
+			source.AddEntry("A", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 053));
+			source.AddEntry("B", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 100));
+			source.AddEntry("C", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 100));
+			source.AddEntry("D", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 100));
+			source.AddEntry("E", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 115));
+			source.AddEntry("F", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 115));
+			source.AddEntry("G", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 115));
+			source.AddEntry("H", LevelFlags.None, new DateTime(2017, 9, 20, 15, 09, 02, 115));
+
+			var index = new MergedLogFileIndex(source);
+			index.Process(new MergedLogFilePendingModification(source, new LogFileSection(0, 8)));
+
+			var indices = index.Get(new LogFileSection(0, 8));
+			indices[0].SourceLineIndex.Should().Be(0);
+			indices[1].SourceLineIndex.Should().Be(1);
+			indices[2].SourceLineIndex.Should().Be(2);
+			indices[3].SourceLineIndex.Should().Be(3);
+			indices[4].SourceLineIndex.Should().Be(4);
+			indices[5].SourceLineIndex.Should().Be(5);
+			indices[6].SourceLineIndex.Should().Be(6);
+			indices[7].SourceLineIndex.Should().Be(7);
+		}
+
 		#region Skip log lines without timestamp
 
 		[Test]