[dotnet] Overwrite internal log file if it already exists

dotnet/src/webdriver/Internal/Logging/FileLogHandler.cs

@@ -22,6 +22,17 @@ public class FileLogHandler : ILogHandler, IDisposable
         /// </summary>
         /// <param name="filePath">The path of the log file.</param>
         public FileLogHandler(string filePath)
+            : this(filePath, overwrite: true)
+        {
+
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FileLogHandler"/> class with the specified file path.
+        /// </summary>
+        /// <param name="filePath">The path of the log file.</param>
+        /// <param name="overwrite">Specifies whether the file should be overwritten if it exists on the disk.</param>
+        public FileLogHandler(string filePath, bool overwrite)
         {
             if (string.IsNullOrEmpty(filePath)) throw new ArgumentException("File log path cannot be null or empty.", nameof(filePath));
 
@@ -31,8 +42,9 @@ public FileLogHandler(string filePath)
                 Directory.CreateDirectory(directory);
             }
 
-            _fileStream = File.Open(filePath, FileMode.OpenOrCreate, FileAccess.Write, FileShare.Read);
-            _fileStream.Seek(0, SeekOrigin.End);
+            var fileMode = overwrite ? FileMode.Create : FileMode.Append;
+
+            _fileStream = File.Open(filePath, fileMode, FileAccess.Write, FileShare.Read);
             _streamWriter = new StreamWriter(_fileStream, System.Text.Encoding.UTF8)
             {
                 AutoFlush = true

dotnet/test/common/Internal/Logging/FileLogHandlerTest.cs

@@ -1,6 +1,7 @@
 using NUnit.Framework;
 using System;
 using System.IO;
+using System.Text.RegularExpressions;
 
 namespace OpenQA.Selenium.Internal.Logging
 {
@@ -34,5 +35,95 @@ public void ShouldHandleLogEvent()
                 File.Delete(tempFile);
             }
         }
+
+        [Test]
+        public void ShouldCreateFileIfDoesNotExist()
+        {
+            var tempFile = Path.GetTempFileName();
+
+            try
+            {
+                using (var fileLogHandler = new FileLogHandler(tempFile))
+                {
+                    fileLogHandler.Handle(new LogEvent(typeof(FileLogHandlerTest), DateTimeOffset.Now, LogEventLevel.Info, "test message"));
+                }
+
+                using (var fileLogHandler2 = new FileLogHandler(tempFile))
+                {
+                    fileLogHandler2.Handle(new LogEvent(typeof(FileLogHandlerTest), DateTimeOffset.Now, LogEventLevel.Info, "test message"));
+                }
+
+                Assert.That(Regex.Matches(File.ReadAllText(tempFile), "test message").Count, Is.EqualTo(1));
+            }
+            finally
+            {
+                File.Delete(tempFile);
+            }
+        }
+
+        [Test]
+        public void ShouldAppendFileIfExists()
+        {
+            var tempFilePath = Path.GetTempPath() + "somefile.log";
+
+            try
+            {
+                using (var fileLogHandler = new FileLogHandler(tempFilePath))
+                {
+                    fileLogHandler.Handle(new LogEvent(typeof(FileLogHandlerTest), DateTimeOffset.Now, LogEventLevel.Info, "test message"));
+                }
+
+                using (var fileLogHandler2 = new FileLogHandler(tempFilePath, overwrite: false))
+                {
+                    fileLogHandler2.Handle(new LogEvent(typeof(FileLogHandlerTest), DateTimeOffset.Now, LogEventLevel.Info, "test message"));
+                }
+
+                Assert.That(Regex.Matches(File.ReadAllText(tempFilePath), "test message").Count, Is.EqualTo(2));
+            }
+            finally
+            {
+                File.Delete(tempFilePath);
+            }
+        }
+
+        [Test]
+        public void ShouldOverwriteFileIfExists()
+        {
+            var tempFile = Path.GetTempFileName();
+
+            try
+            {
+                using (var fileLogHandler = new FileLogHandler(tempFile, overwrite: true))
+                {
+                    fileLogHandler.Handle(new LogEvent(typeof(FileLogHandlerTest), DateTimeOffset.Now, LogEventLevel.Info, "test message"));
+                }
+
+                Assert.That(Regex.Matches(File.ReadAllText(tempFile), "test message").Count, Is.EqualTo(1));
+            }
+            finally
+            {
+                File.Delete(tempFile);
+            }
+        }
+
+        [Test]
+        public void ShouldAppendFileIfDoesNotExist()
+        {
+            var tempFilePath = Path.GetTempPath() + "somefile.log";
+
+            try
+            {
+                using (var fileLogHandler = new FileLogHandler(tempFilePath, overwrite: true))
+                {
+                    fileLogHandler.Handle(new LogEvent(typeof(FileLogHandlerTest), DateTimeOffset.Now, LogEventLevel.Info, "test message"));
+                }
+
+                Assert.That(Regex.Matches(File.ReadAllText(tempFilePath), "test message").Count, Is.EqualTo(1));
+            }
+            finally
+            {
+                File.Delete(tempFilePath);
+            }
+        }
     }
 }