Added FileSystemInfoComparer and tests (#11)

* Added FileSystemInfoComparer and tests

* Rename MockFileSystemTests

* DeleteDirectory should call GetDirectories to get children

---------

Co-authored-by: Brad White <bradselw@pm.me>

src/FileSystem/Comparers/FileSystemInfoComparer.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace DevOptimal.SystemUtilities.FileSystem.Comparers
+{
+    public class FileSystemInfoComparer : IEqualityComparer<FileSystemInfo>
+    {
+        public bool Equals(FileSystemInfo x, FileSystemInfo y)
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                return x.FullName.Equals(y.FullName, StringComparison.OrdinalIgnoreCase);
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            {
+                return x.FullName.Equals(y.FullName, StringComparison.Ordinal);
+            }
+            else
+            {
+                throw new NotSupportedException($"The operating system '{RuntimeInformation.OSDescription}' is not supported.");
+            }
+        }
+
+        public int GetHashCode(FileSystemInfo obj)
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                return obj.FullName.ToLower().GetHashCode();
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            {
+                return obj.FullName.GetHashCode();
+            }
+            else
+            {
+                throw new NotSupportedException($"The operating system '{RuntimeInformation.OSDescription}' is not supported.");
+            }
+        }
+    }
+}

src/FileSystem/MockFileSystem.cs

@@ -3,6 +3,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Text.RegularExpressions;
 
 namespace DevOptimal.SystemUtilities.FileSystem
@@ -21,7 +22,18 @@ public class MockFileSystem : IFileSystem
 
         public MockFileSystem()
         {
-            data = new ConcurrentDictionary<string, byte[]>(StringComparer.OrdinalIgnoreCase);
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                data = new ConcurrentDictionary<string, byte[]>(StringComparer.OrdinalIgnoreCase);
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            {
+                data = new ConcurrentDictionary<string, byte[]>(StringComparer.Ordinal);
+            }
+            else
+            {
+                throw new NotSupportedException($"The operating system '{RuntimeInformation.OSDescription}' is not supported.");
+            }
         }
 
         public void CopyFile(string sourcePath, string destinationPath, bool overwrite)
@@ -81,7 +93,7 @@ public void DeleteDirectory(string path, bool recursive)
                     throw new IOException("A file with the same name and location specified by path exists.");
                 }
 
-                var children = data.Keys.Where(p => Path.GetDirectoryName(p).Equals(path, StringComparison.OrdinalIgnoreCase));
+                var children = GetDirectories(path, "*", SearchOption.TopDirectoryOnly);
 
                 if (children.Any())
                 {

test/FileSystem.Tests/FileSystemInfoComparerTests.cs

@@ -0,0 +1,60 @@
+using DevOptimal.SystemUtilities.FileSystem.Comparers;
+using System.Collections.Generic;
+using System.IO;
+
+namespace DevOptimal.SystemUtilities.FileSystem.Tests
+{
+    [TestClass]
+    public class FileSystemInfoComparerTests
+    {
+        [TestMethod]
+        public void CorrectlyComparesFileInfos()
+        {
+            var files = new HashSet<FileInfo>(new FileSystemInfoComparer())
+            {
+                new FileInfo(@"C:\temp\foo.txt"),
+                new FileInfo(@"C:\temp\FOO.txt")
+            };
+            Assert.AreEqual(1, files.Count);
+
+            files.Add(new FileInfo(@"C:\temp\bar.txt"));
+            Assert.AreEqual(2, files.Count);
+        }
+
+        [TestMethod]
+        public void CorrectlyComparesDirectoryInfos()
+        {
+            var directories = new HashSet<DirectoryInfo>(new FileSystemInfoComparer())
+            {
+                new DirectoryInfo(@"C:\temp\foo"),
+                new DirectoryInfo(@"C:\temp\FOO")
+            };
+            Assert.AreEqual(1, directories.Count);
+
+            directories.Add(new DirectoryInfo(@"C:\temp\bar"));
+            Assert.AreEqual(2, directories.Count);
+        }
+
+        [TestMethod]
+        public void CorrectlyHandlesParentDirectoryReferences()
+        {
+            var files = new HashSet<FileInfo>(new FileSystemInfoComparer())
+            {
+                new FileInfo(@"C:\temp\bar\..\foo.txt"),
+                new FileInfo(@"C:\temp\foo.txt")
+            };
+            Assert.AreEqual(1, files.Count);
+        }
+
+        [TestMethod]
+        public void CorrectlyHandlesCurrentDirectoryReferences()
+        {
+            var files = new HashSet<FileInfo>(new FileSystemInfoComparer())
+            {
+                new FileInfo(@"C:\temp\\.\foo.txt"),
+                new FileInfo(@"C:\temp\foo.txt")
+            };
+            Assert.AreEqual(1, files.Count);
+        }
+    }
+}