Fix several issues with CreateCopyOfAsync extension interface and method

.github/workflows/build.yml

@@ -19,10 +19,10 @@ jobs:
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
-      - name: Install .NET 7 SDK
+      - name: Install .NET SDK
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: '7.0.x'
+          dotnet-version: '8.0.x'
 
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - name: Checkout Repository

.github/workflows/publish.yml

@@ -15,7 +15,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v2
       with:
-        dotnet-version: 7.0.x
+        dotnet-version: 8.0.x
 
     - name: Restore dependencies
       run: dotnet restore

src/Extensions/CopyAndMoveExtensions.cs

@@ -21,24 +21,28 @@ public static async Task<IChildFile> CreateCopyOfAsync(this IModifiableFolder de
     {
         static async Task<IChildFile> CreateCopyOfFallbackAsync(IModifiableFolder destinationFolder, IFile fileToCopy, bool overwrite, CancellationToken cancellationToken = default)
         {
-            // Open the source file
-            using var sourceStream = await fileToCopy.OpenStreamAsync(FileAccess.Read, cancellationToken: cancellationToken);
-
-            // Create the destination file
-            var newFile = await destinationFolder.CreateFileAsync(fileToCopy.Name, overwrite, cancellationToken);
-            using var destinationStream = await newFile.OpenStreamAsync(FileAccess.ReadWrite, cancellationToken: cancellationToken);
             cancellationToken.ThrowIfCancellationRequested();
 
-            // Align stream positions (if possible)
-            if (destinationStream.CanSeek && destinationStream.Position != 0)
-                destinationStream.Seek(0, SeekOrigin.Begin);
+            // If the destination file exists and overwrite is false, it shouldn't be overwritten or returned as-is. Throw an exception instead.
+            if (!overwrite)
+            {
+                try
+                {
+                    var existing = await destinationFolder.GetFirstByNameAsync(fileToCopy.Name, cancellationToken);
+                    if (existing is not null)
+                        throw new FileAlreadyExistsException(fileToCopy.Name);
+                }
+                catch (FileNotFoundException) { }
+            }
 
-            if (sourceStream.CanSeek && sourceStream.Position != 0)
-                sourceStream.Seek(0, SeekOrigin.Begin);
+            // Create the destination file.
+            // 'overwrite: false' would have thrown above if the file exists, so either overwrite is already true or the file doesn't exist yet.
+            // Always overwrite here so the file is empty. 
+            var newFile = await destinationFolder.CreateFileAsync(fileToCopy.Name, overwrite: true, cancellationToken);
+            using var destinationStream = await newFile.OpenStreamAsync(FileAccess.Write, cancellationToken: cancellationToken);
 
-            // Set stream length to zero to clear any existing data.
-            // Otherwise, writing less bytes than already exists would leave extra bytes at the end.
-            destinationStream.SetLength(0);
+            // Open the source file
+            using var sourceStream = await fileToCopy.OpenStreamAsync(FileAccess.Read, cancellationToken: cancellationToken);
 
             // Copy the src into the dest file
             await sourceStream.CopyToAsync(destinationStream, bufferSize: 81920, cancellationToken);
@@ -47,18 +51,6 @@ static async Task<IChildFile> CreateCopyOfFallbackAsync(IModifiableFolder destin
         }
 
         cancellationToken.ThrowIfCancellationRequested();
-
-        // If the destination file exists and overwrite is false, it shouldn't be overwritten or returned as-is. Throw an exception instead.
-        if (!overwrite)
-        {
-            try
-            {
-                var existing = await destinationFolder.GetFirstByNameAsync(fileToCopy.Name, cancellationToken);
-                if (existing is not null)
-                    throw new FileAlreadyExistsException(fileToCopy.Name);
-            }
-            catch (FileNotFoundException) { }
-        }
 
         // If the destination folder declares a non-fallback copy path, try that.
         // Provide fallback in case this file is not a handled type.

src/Memory/MemoryFile.cs

@@ -56,6 +56,7 @@ public Task<Stream> OpenStreamAsync(FileAccess accessMode = FileAccess.Read, Can
             if (accessMode == 0)
                 throw new ArgumentOutOfRangeException(nameof(accessMode), $"{nameof(FileAccess)}.{accessMode} is not valid here.");
 
+            _memoryStream.Position = 0;
             return Task.FromResult<Stream>(new NonDisposableStreamWrapper(_memoryStream));
         }
     }

src/System/IO/SystemFolder.cs

@@ -246,18 +246,18 @@ public async Task<IChildFile> CreateCopyOfAsync(IFile fileToCopy, bool overwrite
         // Handle using System.IO
         var newPath = global::System.IO.Path.Combine(Path, systemFile.Name);
 
-        // If the source and destination are the same, there's no need to copy.
-        if (systemFile.Path == newPath)
-            return new SystemFile(newPath);
-
         if (File.Exists(newPath))
         {
             if (!overwrite)
-                return new SystemFile(newPath, noValidation: true);
+                throw new FileAlreadyExistsException(fileToCopy.Name);
 
             File.Delete(newPath);
         }
 
+        // If the source and destination are the same, there's no need to copy.
+        if (systemFile.Path == newPath)
+            return systemFile;
+
         File.Copy(systemFile.Path, newPath, overwrite);
 
         return new SystemFile(newPath, noValidation: true);

tests/OwlCore.Storage.Tests/Archive/ZipArchive/InMemIFileTests.cs → tests/OwlCore.Storage.Tests/Archive/ZipArchive/ZipArchiveEntryFile_FileInMemory_Tests.cs

@@ -9,7 +9,7 @@ namespace OwlCore.Storage.Tests.Archive.ZipArchive;
 /// A test suite for <see cref="ZipArchiveEntryFile"/>s created entirely in memory.
 /// </summary>
 [TestClass]
-public class InMemIFileTests : CommonIFileTests
+public class ZipArchiveEntryFile_FileInMemory_Tests : CommonIFileTests
 {
     // Required for base class to perform common tests.
     public override Task<IFile> CreateFileAsync()

tests/OwlCore.Storage.Tests/Archive/ZipArchive/IFileTests.cs → tests/OwlCore.Storage.Tests/Archive/ZipArchive/ZipArchiveEntryFile_FileOnDisk_Tests.cs

@@ -6,7 +6,7 @@
 namespace OwlCore.Storage.Tests.Archive.ZipArchive;
 
 [TestClass]
-public class IFileTests : CommonIFileTests
+public class ZipArchiveEntryFile_FileOnDisk_Tests : CommonIFileTests
 {
     // Required for base class to perform common tests.
     public override async Task<IFile> CreateFileAsync()

tests/OwlCore.Storage.Tests/Archive/ZipArchive/InMemIFolderTests.cs → tests/OwlCore.Storage.Tests/Archive/ZipArchive/ZipArchiveFolder_FileInMemory_Tests.cs

@@ -9,7 +9,7 @@ namespace OwlCore.Storage.Tests.Archive.ZipArchive;
 /// A test suite for <see cref="ZipArchiveFolder"/>s created entirely in memory.
 /// </summary>
 [TestClass]
-public class InMemIFolderTests : CommonIModifiableFolderTests
+public class ZipArchiveFolder_FileInMemory_Tests : CommonIModifiableFolderTests
 {
     // Required for base class to perform common tests.
     public override Task<IModifiableFolder> CreateModifiableFolderAsync()

tests/OwlCore.Storage.Tests/Archive/ZipArchive/IFolderTests.cs → tests/OwlCore.Storage.Tests/Archive/ZipArchive/ZipArchiveFolder_FileOnDisk_Tests.cs

@@ -6,13 +6,13 @@
 namespace OwlCore.Storage.Tests.Archive.ZipArchive;
 
 [TestClass]
-public class IFolderTests : CommonIModifiableFolderTests
+public class ZipArchiveFolder_FileOnDisk_Tests : CommonIModifiableFolderTests
 {
     // Required for base class to perform common tests.
-    public override async Task<IModifiableFolder> CreateModifiableFolderAsync()
+    public override Task<IModifiableFolder> CreateModifiableFolderAsync()
     {
         var sourceFile = new SystemFile(CreateEmptyArchiveOnDisk());
-        return new ZipArchiveFolder(sourceFile);
+        return Task.FromResult<IModifiableFolder>(new ZipArchiveFolder(sourceFile));
     }
 
     public override async Task<IModifiableFolder> CreateModifiableFolderWithItems(int fileCount, int folderCount)

tests/OwlCore.Storage.Tests/Memory/IFolderTests.cs → tests/OwlCore.Storage.Tests/Memory/MemoryFolderTests.cs

@@ -4,7 +4,7 @@
 namespace OwlCore.Storage.Tests.Memory;
 
 [TestClass]
-public class IFolderTests : CommonIModifiableFolderTests
+public class MemoryFolderTests : CommonIModifiableFolderTests
 {
     // Required for base class to perform common tests.
     public override Task<IModifiableFolder> CreateModifiableFolderAsync()

tests/OwlCore.Storage.Tests/OwlCore.Storage.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 

tests/OwlCore.Storage.Tests/SystemIO/IFileTests.cs → tests/OwlCore.Storage.Tests/SystemIO/SystemFileTests.cs

@@ -4,7 +4,7 @@
 namespace OwlCore.Storage.Tests.SystemIO;
 
 [TestClass]
-public class IFileTests : CommonIFileTests
+public class SystemFileTests : CommonIFileTests
 {
     // Required for base class to perform common tests.
     public override async Task<IFile> CreateFileAsync()

tests/OwlCore.Storage.Tests/SystemIO/IFolderTests.cs → tests/OwlCore.Storage.Tests/SystemIO/SystemFolderTests.cs

@@ -4,7 +4,7 @@
 namespace OwlCore.Storage.Tests.SystemIO;
 
 [TestClass]
-public class IFolderTests : CommonIModifiableFolderTests
+public class SystemFolderTests : CommonIModifiableFolderTests
 {
     public override Task<IModifiableFolder> CreateModifiableFolderAsync()
     {