feat: add testability for DriveInfo (#1094)

* feat: add testability for drives

* review comments

---------

Co-authored-by: Valentin Breuß <vbreuss@gmail.com>

src/TestableIO.System.IO.Abstractions.TestingHelpers/IMockFileDataAccessor.cs

@@ -23,6 +23,13 @@ public interface IMockFileDataAccessor : IFileSystem
         /// <returns>The file. <see langword="null"/> if the file does not exist.</returns>
         MockFileData GetFile(string path);
 
+        /// <summary>
+        /// Gets a drive.
+        /// </summary>
+        /// <param name="name">The name of the drive to get.</param>
+        /// <returns>The drive. <see langword="null"/> if the drive does not exist.</returns>
+        MockDriveData GetDrive(string name);
+
         /// <summary>
         /// </summary>
         void AddFile(string path, MockFileData mockFile);
@@ -31,6 +38,10 @@ public interface IMockFileDataAccessor : IFileSystem
         /// </summary>
         void AddDirectory(string path);
 
+        /// <summary>
+        /// </summary>
+        void AddDrive(string name, MockDriveData mockDrive);
+
         /// <summary>
         /// </summary>
         void AddFileFromEmbeddedResource(string path, Assembly resourceAssembly, string embeddedResourcePath);
@@ -74,6 +85,11 @@ public interface IMockFileDataAccessor : IFileSystem
         /// </summary>
         IEnumerable<string> AllDirectories { get; }
 
+        /// <summary>
+        /// Gets the names of all drives.
+        /// </summary>
+        IEnumerable<string> AllDrives { get; }
+
         /// <summary>
         /// Gets a helper for string operations.
         /// </summary>

src/TestableIO.System.IO.Abstractions.TestingHelpers/MockDriveData.cs

@@ -0,0 +1,76 @@
+
+namespace System.IO.Abstractions.TestingHelpers
+{
+    /// <summary>
+    /// The class represents the associated data of a drive.
+    /// </summary>
+#if FEATURE_SERIALIZABLE
+    [Serializable]
+#endif
+    public class MockDriveData
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MockDriveData"/> class.
+        /// </summary>
+        public MockDriveData()
+        {
+            IsReady = true;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MockDriveData"/> class by copying the given <see cref="MockDriveData"/>.
+        /// </summary>
+        /// <param name="template">The template instance.</param>
+        /// <exception cref="ArgumentNullException">Thrown if <paramref name="template"/> is <see langword="null"/>.</exception>
+        public MockDriveData(MockDriveData template)
+        {
+            if (template == null)
+            {
+                throw new ArgumentNullException(nameof(template));
+            }
+
+            AvailableFreeSpace = template.AvailableFreeSpace;
+            DriveFormat = template.DriveFormat;
+            DriveType = template.DriveType;
+            IsReady = template.IsReady;
+            TotalFreeSpace = template.TotalFreeSpace;
+            TotalSize = template.TotalSize;
+            VolumeLabel = template.VolumeLabel;
+        }
+
+        /// <summary>
+        /// Gets or sets the amount of available free space of the <see cref="MockDriveData"/>, in bytes.
+        /// </summary>
+        public long AvailableFreeSpace { get; set; }
+
+        /// <summary>
+        /// Gets or sets the name of the file system of the <see cref="MockDriveData"/>, such as NTFS or FAT32.
+        /// </summary>
+        public string DriveFormat { get; set; }
+
+        /// <summary>
+        /// Gets or sets the drive type of the <see cref="MockDriveData"/>, such as CD-ROM, removable, network, or fixed.
+        /// </summary>
+        public DriveType DriveType { get; set; }
+
+        /// <summary>
+        /// Gets or sets the value that indicates whether the <see cref="MockDriveData"/> is ready.
+        /// </summary>
+        public bool IsReady { get; set; }
+
+        /// <summary>
+        /// Gets or sets the total amount of free space available on the <see cref="MockDriveData"/>, in bytes.
+        /// </summary>
+        public long TotalFreeSpace { get; set; }
+
+        /// <summary>
+        /// Gets or sets the total size of storage space on the <see cref="MockDriveData"/>, in bytes.
+        /// </summary>
+        public long TotalSize { get; set; }
+
+        /// <summary>
+        /// Gets or sets the volume label of the <see cref="MockDriveData"/>.
+        /// </summary>
+        public string VolumeLabel { get; set; }
+    }
+}

src/TestableIO.System.IO.Abstractions.TestingHelpers/MockDriveInfo.cs

@@ -7,51 +7,60 @@
     public class MockDriveInfo : DriveInfoBase
     {
         private readonly IMockFileDataAccessor mockFileDataAccessor;
+        private readonly string name;
 
         /// <inheritdoc />
         public MockDriveInfo(IMockFileDataAccessor mockFileDataAccessor, string name) : base(mockFileDataAccessor?.FileSystem)
         {
             this.mockFileDataAccessor = mockFileDataAccessor ?? throw new ArgumentNullException(nameof(mockFileDataAccessor));
+            this.name = mockFileDataAccessor.PathVerifier.NormalizeDriveName(name);
+        }
 
-            if (name == null)
+        /// <inheritdoc />
+        public override long AvailableFreeSpace
+        {
+            get
             {
-                throw new ArgumentNullException(nameof(name));
+                var mockDriveData = GetMockDriveData();
+                return mockDriveData.AvailableFreeSpace;
             }
+        }
 
-            const string DRIVE_SEPARATOR = @":\";
-
-            if (name.Length == 1
-                || (name.Length == 2 && name[1] == ':')
-                || (name.Length == 3 && mockFileDataAccessor.StringOperations.EndsWith(name, DRIVE_SEPARATOR)))
+        /// <inheritdoc />
+        public override string DriveFormat
+        {
+            get
             {
-                name = name[0] + DRIVE_SEPARATOR;
+                var mockDriveData = GetMockDriveData();
+                return mockDriveData.DriveFormat;
             }
-            else
-            {
-                mockFileDataAccessor.PathVerifier.CheckInvalidPathChars(name);
-                name = mockFileDataAccessor.Path.GetPathRoot(name);
+        }
 
-                if (string.IsNullOrEmpty(name) || mockFileDataAccessor.StringOperations.StartsWith(name, @"\\"))
-                {
-                    throw new ArgumentException(
-                        @"Object must be a root directory (""C:\"") or a drive letter (""C"").");
-                }
+        /// <inheritdoc />
+        public override DriveType DriveType
+        {
+            get
+            {
+                var mockDriveData = GetMockDriveData();
+                return mockDriveData.DriveType;
             }
-
-            Name = name;
-            IsReady = true;
         }
 
         /// <inheritdoc />
-        public new long AvailableFreeSpace { get; set; }
-        /// <inheritdoc />
-        public new string DriveFormat { get; set; }
-        /// <inheritdoc />
-        public new DriveType DriveType { get; set; }
-        /// <inheritdoc />
-        public new bool IsReady { get; protected set; }
+        public override bool IsReady
+        {
+            get
+            {
+                var mockDriveData = GetMockDriveData();
+                return mockDriveData.IsReady;
+            }
+        }
+
         /// <inheritdoc />
-        public override string Name { get; protected set; }
+        public override string Name
+        {
+            get { return name; }
+        }
 
         /// <inheritdoc />
         public override IDirectoryInfo RootDirectory
@@ -63,16 +72,50 @@ public override IDirectoryInfo RootDirectory
         }
 
         /// <inheritdoc />
-        public override string ToString()
+        public override long TotalFreeSpace
         {
-            return Name;
+            get
+            {
+                var mockDriveData = GetMockDriveData();
+                return mockDriveData.TotalFreeSpace;
+            }
         }
 
         /// <inheritdoc />
-        public new long TotalFreeSpace { get; protected set; }
+        public override long TotalSize
+        {
+            get
+            {
+                var mockDriveData = GetMockDriveData();
+                return mockDriveData.TotalSize;
+            }
+        }
+
         /// <inheritdoc />
-        public new long TotalSize { get; protected set; }
+        public override string VolumeLabel
+        {
+            get
+            {
+                var mockDriveData = GetMockDriveData();
+                return mockDriveData.VolumeLabel;
+            }
+            set
+            {
+                var mockDriveData = GetMockDriveData();
+                mockDriveData.VolumeLabel = value;
+            }
+        }
+
         /// <inheritdoc />
-        public override string VolumeLabel { get; set; }
+        public override string ToString()
+        {
+            return Name;
+        }
+
+        private MockDriveData GetMockDriveData()
+        {
+            return mockFileDataAccessor.GetDrive(name)
+                ?? throw CommonExceptions.FileNotFound(name);
+        }
     }
 }

src/TestableIO.System.IO.Abstractions.TestingHelpers/MockDriveInfoFactory.cs

@@ -23,15 +23,8 @@ public IFileSystem FileSystem
         /// <inheritdoc />
         public IDriveInfo[] GetDrives()
         {
-            var driveLetters = new HashSet<string>(new DriveEqualityComparer(mockFileSystem));
-            foreach (var path in mockFileSystem.AllPaths)
-            {
-                var pathRoot = mockFileSystem.Path.GetPathRoot(path);
-                driveLetters.Add(pathRoot);
-            }
-
             var result = new List<DriveInfoBase>();
-            foreach (string driveLetter in driveLetters)
+            foreach (string driveLetter in mockFileSystem.AllDrives)
             {
                 try
                 {