[265] Add file upload to allow mocking of file operations (#266)

* [265] Add file upload to allow mocking of file operations

* [265] Fix failing test

* Update code + add tests

* LocalFileSystemHandlerTests

* 1.0.13

* Fixed the file post to create the mapping folder if none exists to begin with, otherwise the file upload fails with 404 (can't find the folder to upload to).

* fix tests

* add more tests for LocalFileSystemHandler

* Added the head method for files to check if a file exists without returning it as a body.

* Add a test and fix the response message (head requires no body).

* Fix newline

* Fix newline.

* Fix the number of mapping tests

* Update tests and update client-interface-api

* Cleanup "MappingConverter.cs"

examples/WireMock.Net.Console.Net452.Classic/CustomFileSystemFileHandler.cs

@@ -49,5 +49,39 @@ namespace WireMock.Net.ConsoleApplication
         {
             return File.ReadAllBytes(Path.GetFileName(path) == path ? Path.Combine(GetMappingFolder(), path) : path);
         }
+
+        /// <inheritdoc cref="IFileSystemHandler.FileExists"/>
+        public bool FileExists(string path)
+        {
+            return File.Exists(AdjustPath(path));
+        }
+
+        /// <inheritdoc cref="IFileSystemHandler.WriteFile(string, byte[])"/>
+        public void WriteFile(string path, byte[] bytes)
+        {
+            File.WriteAllBytes(AdjustPath(path), bytes);
+        }
+
+        /// <inheritdoc cref="IFileSystemHandler.DeleteFile"/>
+        public void DeleteFile(string path)
+        {
+            File.Delete(AdjustPath(path));
+        }
+
+        /// <inheritdoc cref="IFileSystemHandler.ReadFile"/>
+        public byte[] ReadFile(string path)
+        {
+            return File.ReadAllBytes(AdjustPath(path));
+        }
+
+        /// <summary>
+        /// Adjusts the path to the MappingFolder.
+        /// </summary>
+        /// <param name="path">The path.</param>
+        /// <returns>Adjusted path</returns>
+        private string AdjustPath(string path)
+        {
+            return Path.Combine(GetMappingFolder(), path);
+        }
     }
 }