feat: set Creation, LastAccess and LastWrite time for files (#875)

Implements #872 
Adjust `CreationTime`, `LastAccessTime` and `LastWriteTime` when interacting with files in the `MockFileSystem`.

Provides a means to mock the used DateTime by calling e.g.
```csharp
var fixedTime = new DateTime(2022, 01, 01);
var fileSystem = new MockFileSystem().MockTime(() => fixedTime);
// All times will now be set to the fixedTime.
```

Implementes the following logic in MockFile:
*All these cases are covered by unit tests in MockFileAdjustTimesTest*
- When creating files
   CreationTime, LastAccessTime and LastWriteTime are set to the current time
- When changing files (`WriteAllText`, `WriteAllBytes`, `AppendAllText`, `OpenWrite`, `Open`)
   LastAccessTime and LastWriteTime are set to the current time
   CreationTime is left unchanged
- When reading files (`ReadAllText`, `ReadAllLines`, `ReadAllBytes`, `OpenRead`)
   LastAccessTime is set to the current time
   CreationTime and LastWriteTime are left unchanged
- When setting attributes or ACLs (`SetAttributes`, `SetAccessControl`)
   LastAccessTime is set to the current time
   CreationTime and LastWriteTime are left unchanged
- When moving files (`Move`)
   LastAccessTime is set to the current time
   CreationTime and LastWriteTime are left unchanged
- When copying files (`Copy`)
   CreationTime and LastAccessTime of the copied file in the destination directory is set to the current time
   LastWriteTime and all times of the source file are left unchanged

Author: vbreuss

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

@@ -8,6 +8,14 @@ namespace System.IO.Abstractions.TestingHelpers
     /// </summary>
     public interface IMockFileDataAccessor : IFileSystem
     {
+        /// <summary>
+        /// Adjust the times of the <paramref name="fileData"/>.
+        /// </summary>
+        /// <param name="fileData">The <see cref="MockFileData"/> for which the times should be adjusted.</param>
+        /// <param name="timeAdjustments">The adjustments to make on the <see cref="MockFileData"/>.</param>
+        /// <returns>The adjusted file.</returns>
+        MockFileData AdjustTimes(MockFileData fileData, TimeAdjustments timeAdjustments);
+
         /// <summary>
         /// Gets a file.
         /// </summary>

src/System.IO.Abstractions.TestingHelpers/MockDirectoryInfo.cs

@@ -62,15 +62,15 @@ public override FileAttributes Attributes
         /// <inheritdoc />
         public override DateTime CreationTime
         {
-            get { return GetMockFileDataForRead().CreationTime.DateTime; }
+            get { return GetMockFileDataForRead().CreationTime.LocalDateTime; }
             set { GetMockFileDataForWrite().CreationTime = value; }
         }
 
         /// <inheritdoc />
         public override DateTime CreationTimeUtc
         {
             get { return GetMockFileDataForRead().CreationTime.UtcDateTime; }
-            set { GetMockFileDataForWrite().CreationTime = value.ToLocalTime(); }
+            set { GetMockFileDataForWrite().CreationTime = value; }
         }
 
         /// <inheritdoc />
@@ -114,29 +114,29 @@ public override string FullName
         /// <inheritdoc />
         public override DateTime LastAccessTime
         {
-            get { return GetMockFileDataForRead().LastAccessTime.DateTime; }
+            get { return GetMockFileDataForRead().LastAccessTime.LocalDateTime; }
             set { GetMockFileDataForWrite().LastAccessTime = value; }
         }
 
         /// <inheritdoc />
         public override DateTime LastAccessTimeUtc
         {
             get { return GetMockFileDataForRead().LastAccessTime.UtcDateTime; }
-            set { GetMockFileDataForWrite().LastAccessTime = value.ToLocalTime(); }
+            set { GetMockFileDataForWrite().LastAccessTime = value; }
         }
 
         /// <inheritdoc />
         public override DateTime LastWriteTime
         {
-            get { return GetMockFileDataForRead().LastWriteTime.DateTime; }
+            get { return GetMockFileDataForRead().LastWriteTime.LocalDateTime; }
             set { GetMockFileDataForWrite().LastWriteTime = value; }
         }
 
         /// <inheritdoc />
         public override DateTime LastWriteTimeUtc
         {
             get { return GetMockFileDataForRead().LastWriteTime.UtcDateTime; }
-            set { GetMockFileDataForWrite().LastWriteTime = value.ToLocalTime(); }
+            set { GetMockFileDataForWrite().LastWriteTime = value; }
         }
 
 #if FEATURE_FILE_SYSTEM_INFO_LINK_TARGET

src/System.IO.Abstractions.TestingHelpers/MockFile.cs

@@ -55,12 +55,13 @@ public override void AppendAllText(string path, string contents, Encoding encodi
             if (!mockFileDataAccessor.FileExists(path))
             {
                 VerifyDirectoryExists(path);
-                mockFileDataAccessor.AddFile(path, new MockFileData(contents, encoding));
+                mockFileDataAccessor.AddFile(path, mockFileDataAccessor.AdjustTimes(new MockFileData(contents, encoding), TimeAdjustments.All));
             }
             else
             {
                 var file = mockFileDataAccessor.GetFile(path);
                 file.CheckFileAccess(path, FileAccess.Write);
+                mockFileDataAccessor.AdjustTimes(file, TimeAdjustments.LastAccessTime | TimeAdjustments.LastWriteTime);
                 var bytesToAppend = encoding.GetBytes(contents);
                 file.Contents = file.Contents.Concat(bytesToAppend).ToArray();
             }
@@ -124,7 +125,7 @@ public override void Copy(string sourceFileName, string destFileName, bool overw
             var sourceFileData = mockFileDataAccessor.GetFile(sourceFileName);
             sourceFileData.CheckFileAccess(sourceFileName, FileAccess.Read);
             var destFileData = new MockFileData(sourceFileData);
-            destFileData.CreationTime = destFileData.LastAccessTime = DateTime.Now;
+            mockFileDataAccessor.AdjustTimes(destFileData, TimeAdjustments.CreationTime | TimeAdjustments.LastAccessTime);
             mockFileDataAccessor.AddFile(destFileName, destFileData);
         }
 
@@ -151,6 +152,7 @@ private Stream CreateInternal(string path, FileAccess access, FileOptions option
             VerifyDirectoryExists(path);
 
             var mockFileData = new MockFileData(new byte[0]);
+            mockFileDataAccessor.AdjustTimes(mockFileData, TimeAdjustments.All);
             mockFileDataAccessor.AddFile(path, mockFileData);
             return OpenInternal(path, FileMode.Open, access, options);
         }
@@ -188,7 +190,7 @@ public override IFileSystemInfo CreateSymbolicLink(string path, string pathToTar
             var sourceFileData = mockFileDataAccessor.GetFile(pathToTarget);
             sourceFileData.CheckFileAccess(pathToTarget, FileAccess.Read);
             var destFileData = new MockFileData(new byte[0]);
-            destFileData.CreationTime = destFileData.LastAccessTime = DateTime.Now;
+            mockFileDataAccessor.AdjustTimes(destFileData, TimeAdjustments.CreationTime | TimeAdjustments.LastAccessTime);
             destFileData.LinkTarget = pathToTarget;
             mockFileDataAccessor.AddFile(path, destFileData);
 
@@ -436,7 +438,7 @@ public override void Move(string sourceFileName, string destFileName)
             VerifyDirectoryExists(destFileName);
 
             mockFileDataAccessor.RemoveFile(sourceFileName);
-            mockFileDataAccessor.AddFile(destFileName, new MockFileData(sourceFile));
+            mockFileDataAccessor.AddFile(destFileName, mockFileDataAccessor.AdjustTimes(new MockFileData(sourceFile), TimeAdjustments.LastAccessTime));
         }
 
 #if FEATURE_FILE_MOVE_WITH_OVERWRITE
@@ -480,9 +482,9 @@ public override void Move(string sourceFileName, string destFileName, bool overw
                 throw CommonExceptions.ProcessCannotAccessFileInUse();
             }
             VerifyDirectoryExists(destFileName);
-
+            
             mockFileDataAccessor.RemoveFile(sourceFileName);
-            mockFileDataAccessor.AddFile(destFileName, new MockFileData(sourceFile));
+            mockFileDataAccessor.AddFile(destFileName, mockFileDataAccessor.AdjustTimes(new MockFileData(sourceFile), TimeAdjustments.LastAccessTime));
         }
 #endif
 
@@ -539,6 +541,12 @@ private Stream OpenInternal(
 
             var mockFileData = mockFileDataAccessor.GetFile(path);
             mockFileData.CheckFileAccess(path, access);
+            var timeAdjustments = TimeAdjustments.LastAccessTime;
+            if (access.HasFlag(FileAccess.Write))
+            {
+                timeAdjustments |= TimeAdjustments.LastWriteTime;
+            }
+            mockFileDataAccessor.AdjustTimes(mockFileData, timeAdjustments);
 
             return new MockFileStream(mockFileDataAccessor, path, mode, access, options);
         }
@@ -578,7 +586,9 @@ public override byte[] ReadAllBytes(string path)
                 throw CommonExceptions.FileNotFound(path);
             }
             mockFileDataAccessor.GetFile(path).CheckFileAccess(path, FileAccess.Read);
-            return mockFileDataAccessor.GetFile(path).Contents.ToArray();
+            var fileData = mockFileDataAccessor.GetFile(path);
+            mockFileDataAccessor.AdjustTimes(fileData, TimeAdjustments.LastAccessTime);
+            return fileData.Contents.ToArray();
         }
 
         /// <inheritdoc />
@@ -590,10 +600,11 @@ public override string[] ReadAllLines(string path)
             {
                 throw CommonExceptions.FileNotFound(path);
             }
-            mockFileDataAccessor.GetFile(path).CheckFileAccess(path, FileAccess.Read);
+            var fileData = mockFileDataAccessor.GetFile(path);
+            fileData.CheckFileAccess(path, FileAccess.Read);
+            mockFileDataAccessor.AdjustTimes(fileData, TimeAdjustments.LastAccessTime);
 
-            return mockFileDataAccessor
-                .GetFile(path)
+            return fileData
                 .TextContents
                 .SplitLines();
         }
@@ -613,9 +624,11 @@ public override string[] ReadAllLines(string path, Encoding encoding)
                 throw CommonExceptions.FileNotFound(path);
             }
 
-            mockFileDataAccessor.GetFile(path).CheckFileAccess(path, FileAccess.Read);
+            var fileData = mockFileDataAccessor.GetFile(path);
+            fileData.CheckFileAccess(path, FileAccess.Read);
+            mockFileDataAccessor.AdjustTimes(fileData, TimeAdjustments.LastAccessTime);
 
-            using (var ms = new MemoryStream(mockFileDataAccessor.GetFile(path).Contents))
+            using (var ms = new MemoryStream(fileData.Contents))
             using (var sr = new StreamReader(ms, encoding))
             {
                 return sr.ReadToEnd().SplitLines();
@@ -713,6 +726,7 @@ public override void SetAccessControl(string path, FileSecurity fileSecurity)
             }
 
             var fileData = mockFileDataAccessor.GetFile(path);
+            mockFileDataAccessor.AdjustTimes(fileData, TimeAdjustments.LastAccessTime);
             fileData.AccessControl = fileSecurity;
         }
 
@@ -736,6 +750,7 @@ public override void SetAttributes(string path, FileAttributes fileAttributes)
             }
             else
             {
+                mockFileDataAccessor.AdjustTimes(possibleFileData, TimeAdjustments.LastAccessTime);
                 possibleFileData.Attributes = fileAttributes;
             }
         }
@@ -824,7 +839,7 @@ public override void WriteAllBytes(string path, byte[] bytes)
             mockFileDataAccessor.PathVerifier.IsLegalAbsoluteOrRelative(path, "path");
             VerifyDirectoryExists(path);
 
-            mockFileDataAccessor.AddFile(path, new MockFileData(bytes.ToArray()));
+            mockFileDataAccessor.AddFile(path, mockFileDataAccessor.AdjustTimes(new MockFileData(bytes.ToArray()), TimeAdjustments.All));
         }
 
         /// <summary>
@@ -1094,7 +1109,7 @@ public override void WriteAllText(string path, string contents, Encoding encodin
             VerifyDirectoryExists(path);
 
             MockFileData data = contents == null ? new MockFileData(new byte[0]) : new MockFileData(contents, encoding);
-            mockFileDataAccessor.AddFile(path, data);
+            mockFileDataAccessor.AddFile(path, mockFileDataAccessor.AdjustTimes(data, TimeAdjustments.All));
         }
 
         internal static string ReadAllBytes(byte[] contents, Encoding encoding)
@@ -1110,6 +1125,7 @@ private string ReadAllTextInternal(string path, Encoding encoding)
         {
             var mockFileData = mockFileDataAccessor.GetFile(path);
             mockFileData.CheckFileAccess(path, FileAccess.Read);
+            mockFileDataAccessor.AdjustTimes(mockFileData, TimeAdjustments.LastAccessTime);
             return ReadAllBytes(mockFileData.Contents, encoding);
         }
 

src/System.IO.Abstractions.TestingHelpers/MockFileData.cs

@@ -49,7 +49,10 @@ public class MockFileData
         /// </summary>
         private MockFileData()
         {
-            // empty
+            var now = DateTime.UtcNow;
+            LastWriteTime = now;
+            LastAccessTime = now;
+            CreationTime = now;
         }
 
         /// <summary>
@@ -78,6 +81,7 @@ public MockFileData(string textContents, Encoding encoding)
         /// <param name="contents">The actual content.</param>
         /// <exception cref="ArgumentNullException">Thrown if <paramref name="contents"/> is <see langword="null" />.</exception>
         public MockFileData(byte[] contents)
+            : this()
         {
             Contents = contents ?? throw new ArgumentNullException(nameof(contents));
         }
@@ -126,17 +130,32 @@ public string TextContents
         /// <summary>
         /// Gets or sets the date and time the <see cref="MockFileData"/> was created.
         /// </summary>
-        public DateTimeOffset CreationTime { get; set; } = new DateTimeOffset(2010, 01, 02, 00, 00, 00, TimeSpan.FromHours(4));
+        public DateTimeOffset CreationTime
+        {
+            get { return creationTime; }
+            set{ creationTime = value.ToUniversalTime(); }
+        }
+        private DateTimeOffset creationTime;
 
         /// <summary>
         /// Gets or sets the date and time of the <see cref="MockFileData"/> was last accessed to.
         /// </summary>
-        public DateTimeOffset LastAccessTime { get; set; } = new DateTimeOffset(2010, 02, 04, 00, 00, 00, TimeSpan.FromHours(4));
+        public DateTimeOffset LastAccessTime
+        {
+            get { return lastAccessTime; }
+            set { lastAccessTime = value.ToUniversalTime(); }
+        }
+        private DateTimeOffset lastAccessTime;
 
         /// <summary>
         /// Gets or sets the date and time of the <see cref="MockFileData"/> was last written to.
         /// </summary>
-        public DateTimeOffset LastWriteTime { get; set; } = new DateTimeOffset(2010, 01, 04, 00, 00, 00, TimeSpan.FromHours(4));
+        public DateTimeOffset LastWriteTime
+        {
+            get { return lastWriteTime; }
+            set { lastWriteTime = value.ToUniversalTime(); }
+        }
+        private DateTimeOffset lastWriteTime;
 
 #if FEATURE_FILE_SYSTEM_INFO_LINK_TARGET
         /// <summary>

src/System.IO.Abstractions.TestingHelpers/MockFileInfo.cs

@@ -1,6 +1,5 @@
 using System.Runtime.Versioning;
 using System.Security.AccessControl;
-using System.Text;
 
 namespace System.IO.Abstractions.TestingHelpers
 {
@@ -60,12 +59,12 @@ public override DateTime CreationTime
             get
             {
                 var mockFileData = GetMockFileDataForRead();
-                return mockFileData.CreationTime.DateTime;
+                return mockFileData.CreationTime.LocalDateTime;
             }
             set
             {
                 var mockFileData = GetMockFileDataForWrite();
-                mockFileData.CreationTime = value;
+                mockFileData.CreationTime = AdjustUnspecifiedKind(value, DateTimeKind.Local);
             }
         }
 
@@ -80,7 +79,7 @@ public override DateTime CreationTimeUtc
             set
             {
                 var mockFileData = GetMockFileDataForWrite();
-                mockFileData.CreationTime = value.ToLocalTime();
+                mockFileData.CreationTime = AdjustUnspecifiedKind(value, DateTimeKind.Utc);
             }
         }
 
@@ -117,12 +116,12 @@ public override DateTime LastAccessTime
             get
             {
                 var mockFileData = GetMockFileDataForRead();
-                return mockFileData.LastAccessTime.DateTime;
+                return mockFileData.LastAccessTime.LocalDateTime;
             }
             set
             {
                 var mockFileData = GetMockFileDataForWrite();
-                mockFileData.LastAccessTime = value;
+                mockFileData.LastAccessTime = AdjustUnspecifiedKind(value, DateTimeKind.Local);
             }
         }
 
@@ -137,7 +136,7 @@ public override DateTime LastAccessTimeUtc
             set
             {
                 var mockFileData = GetMockFileDataForWrite();
-                mockFileData.LastAccessTime = value;
+                mockFileData.LastAccessTime = AdjustUnspecifiedKind(value, DateTimeKind.Utc);
             }
         }
 
@@ -147,12 +146,12 @@ public override DateTime LastWriteTime
             get
             {
                 var mockFileData = GetMockFileDataForRead();
-                return mockFileData.LastWriteTime.DateTime;
+                return mockFileData.LastWriteTime.LocalDateTime;
             }
             set
             {
                 var mockFileData = GetMockFileDataForWrite();
-                mockFileData.LastWriteTime = value;
+                mockFileData.LastWriteTime = AdjustUnspecifiedKind(value, DateTimeKind.Local);
             }
         }
 
@@ -167,7 +166,7 @@ public override DateTime LastWriteTimeUtc
             set
             {
                 var mockFileData = GetMockFileDataForWrite();
-                mockFileData.LastWriteTime = value.ToLocalTime();
+                mockFileData.LastWriteTime = AdjustUnspecifiedKind(value, DateTimeKind.Utc);
             }
         }
 
@@ -381,6 +380,16 @@ public override string ToString()
             return originalPath;
         }
 
+        private static DateTime AdjustUnspecifiedKind(DateTime time, DateTimeKind fallbackKind)
+        {
+            if (time.Kind == DateTimeKind.Unspecified)
+            {
+                return DateTime.SpecifyKind(time, fallbackKind);
+            }
+
+            return time;
+        }
+
         private MockFileData GetMockFileDataForRead()
         {
             if (refreshOnNextRead)