Fix MockDirectoryInfo GetFiles for UNC paths caused by bug in StringExtensions.NormalizeSlashes (#421) (#422)

Fixes #421

Author: DeveloperGuo

System.IO.Abstractions.TestingHelpers.Tests/MockDirectoryInfoTests.cs

@@ -55,6 +55,29 @@ public void MockDirectoryInfo_Exists(string path, bool expected)
             Assert.That(result, Is.EqualTo(expected));
         }
 
+        [Test]
+        [WindowsOnly(WindowsSpecifics.UNCPaths)]
+        public void MockDirectoryInfo_GetFiles_ShouldWorkWithUNCPath()
+        {
+            var fileName = XFS.Path(@"\\unc\folder\file.txt");
+            var directoryName = XFS.Path(@"\\unc\folder");
+            // Arrange
+            var fileSystem = new MockFileSystem(new Dictionary<string, MockFileData>
+            {
+                {fileName, ""}
+            });
+
+            var directoryInfo = new MockDirectoryInfo(fileSystem, directoryName);
+
+            // Act
+            var files = directoryInfo.GetFiles();
+
+            // Assert
+            Assert.AreEqual(fileName, files[0].FullName);
+        }
+
+
+
         [Test]
         public void MockDirectoryInfo_FullName_ShouldReturnFullNameWithoutIncludingTrailingPathDelimiter()
         {

System.IO.Abstractions.TestingHelpers.Tests/StringExtensionsTests.cs

@@ -112,5 +112,13 @@ public void TrimSlashes_SlashRoot_PreserveSlashRoot()
         {
             Assert.AreEqual("/", "/".TrimSlashes());
         }
+
+        [TestCase(@"\\unc\folder\file.txt", @"\\unc\folder\file.txt")]
+        [TestCase(@"//unc/folder/file.txt", @"\\unc\folder\file.txt")]
+        [WindowsOnly(WindowsSpecifics.UNCPaths)]
+        public void NormalizeSlashes_KeepsUNCPathPrefix(string path, string expectedValue)
+        {
+            Assert.AreEqual(expectedValue, path.NormalizeSlashes());
+        }
     }
 }

System.IO.Abstractions.TestingHelpers/StringExtensions.cs

@@ -99,7 +99,7 @@ public static string NormalizeSlashes(this string path)
 
             // UNC Paths start with double slash but no reason
             // to have more than 2 slashes at the start of a path
-            if (XFS.IsWindowsPlatform() && prefixSeps.Length > 2)
+            if (XFS.IsWindowsPlatform() && prefixSeps.Length >= 2)
             {
                 prefixSeps = prefixSeps.Substring(0, 2);
             }