Made Plugin Folder Unit tests & Expanding enviroment search (#6600)

* Made Plugin Folder Unit tests. Fixes '>' not recursive searching (with max). Added that paths with an UnauthorizedAccessException are ignored. Added expanding enviroment search.

* Fixed some merging errors

* Added feedback from review

* Made the change that  ryanbodrug-microsoft suggested

* Stupid merge request... fixed

Co-authored-by: p-storm <paul.de.man@gmail.com>

src/modules/launcher/Plugins/Microsoft.Plugin.Folder/Sources/QueryFileSystemInfo.cs

@@ -0,0 +1,74 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Wox.Infrastructure.FileSystemHelper;
+
+namespace Microsoft.Plugin.Folder.Sources
+{
+    public class QueryFileSystemInfo : DirectoryWrapper,  IQueryFileSystemInfo
+    {
+        public IEnumerable<DisplayFileInfo> MatchFileSystemInfo(string search, string incompleteName, SearchOption searchOption)
+        {
+            // search folder and add results
+            var directoryInfo = new DirectoryInfo(search);
+            var fileSystemInfos = directoryInfo.EnumerateFileSystemInfos(incompleteName, searchOption);
+
+            return SafeEnumerateFileSystemInfos(fileSystemInfos)
+                .Where(fileSystemInfo => (fileSystemInfo.Attributes & FileAttributes.Hidden) != FileAttributes.Hidden)
+                .Select(CreateDisplayFileInfo);
+        }
+
+        private static IEnumerable<FileSystemInfo> SafeEnumerateFileSystemInfos(IEnumerable<FileSystemInfo> fileSystemInfos)
+        {
+            using (var enumerator = fileSystemInfos.GetEnumerator())
+            {
+                while (true)
+                {
+                    FileSystemInfo currentFileSystemInfo;
+                    try
+                    {
+                        if (!enumerator.MoveNext())
+                        {
+                            break;
+                        }
+
+                        currentFileSystemInfo = enumerator.Current;
+                    }
+                    catch (UnauthorizedAccessException)
+                    {
+                        continue;
+                    }
+
+                    yield return currentFileSystemInfo;
+                }
+            }
+        }
+
+        private static DisplayFileInfo CreateDisplayFileInfo(FileSystemInfo fileSystemInfo)
+        {
+            return new DisplayFileInfo()
+            {
+                Name = fileSystemInfo.Name,
+                FullName = fileSystemInfo.FullName,
+                Type = GetDisplayType(fileSystemInfo),
+            };
+        }
+
+        private static DisplayType GetDisplayType(FileSystemInfo fileSystemInfo)
+        {
+            if (fileSystemInfo is DirectoryInfo)
+            {
+                return DisplayType.Directory;
+            }
+            else
+            {
+                return DisplayType.File;
+            }
+        }
+    }
+}