feat: implement MockFile.ReadLinesAsync

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

@@ -1,6 +1,7 @@
 #if FEATURE_ASYNC_FILE
 
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
@@ -23,7 +24,7 @@ partial class MockFile
 
  /// <inheritdoc />
  public override Task AppendAllTextAsync(string path, string contents, CancellationToken cancellationToken = default(CancellationToken)) =>
- AppendAllTextAsync(path, contents, MockFileData.DefaultEncoding, cancellationToken);
+AppendAllTextAsync(path, contents, MockFileData.DefaultEncoding, cancellationToken);
 
 
  /// <inheritdoc />
@@ -43,7 +44,7 @@ partial class MockFile
 
  /// <inheritdoc />
  public override Task<string[]> ReadAllLinesAsync(string path, CancellationToken cancellationToken = default(CancellationToken)) =>
- ReadAllLinesAsync(path, MockFileData.DefaultEncoding, cancellationToken);
+ReadAllLinesAsync(path, MockFileData.DefaultEncoding, cancellationToken);
 
  /// <inheritdoc />
 
@@ -55,7 +56,7 @@ partial class MockFile
 
  /// <inheritdoc />
  public override Task<string> ReadAllTextAsync(string path, CancellationToken cancellationToken) =>
- ReadAllTextAsync(path, MockFileData.DefaultEncoding, cancellationToken);
+ReadAllTextAsync(path, MockFileData.DefaultEncoding, cancellationToken);
 
 
  /// <inheritdoc />
@@ -67,17 +68,16 @@ public override Task<string> ReadAllTextAsync(string path, Encoding encoding, Ca
 
 #if FEATURE_READ_LINES_ASYNC
  /// <inheritdoc />
- public override IAsyncEnumerable<string> ReadLinesAsync(string path,
- CancellationToken cancellationToken = default)
- {
- throw CommonExceptions.NotImplemented();
- }
+ public override IAsyncEnumerable<string> ReadLinesAsync(string path, CancellationToken cancellationToken = default) =>
+ ReadLinesAsync(path, MockFileData.DefaultEncoding, cancellationToken);
 
  /// <inheritdoc />
- public override IAsyncEnumerable<string> ReadLinesAsync(string path, Encoding encoding,
- CancellationToken cancellationToken = default)
+ public override async IAsyncEnumerable<string> ReadLinesAsync(string path, Encoding encoding,
+[EnumeratorCancellation] CancellationToken cancellationToken = default)
  {
- throw CommonExceptions.NotImplemented();
+ var lines = await ReadAllLinesAsync(path, encoding, cancellationToken);
+ foreach (var line in lines)
+ yield return line;
  }
 #endif
 
@@ -103,7 +103,7 @@ public override Task WriteAllLinesAsync(string path, IEnumerable<string> content
 
  /// <inheritdoc />
  public override Task WriteAllTextAsync(string path, string contents, CancellationToken cancellationToken) =>
-WriteAllTextAsync(path, contents, MockFileData.DefaultEncoding, cancellationToken);
+WriteAllTextAsync(path, contents, MockFileData.DefaultEncoding, cancellationToken);
 
  /// <inheritdoc />
  public override Task WriteAllTextAsync(string path, string contents, Encoding encoding, CancellationToken cancellationToken)
@@ -115,4 +115,4 @@ public override Task WriteAllTextAsync(string path, string contents, Encoding en
  }
 }
 
-#endif
+#endif

tests/TestableIO.System.IO.Abstractions.TestingHelpers.Tests/MockFileReadAllLinesTests.cs

@@ -1,16 +1,16 @@
 namespace System.IO.Abstractions.TestingHelpers.Tests
 {
  using Collections.Generic;
+ using Collections.Specialized;
+ using Threading;
+ using Threading.Tasks;
 
  using NUnit.Framework;
 
  using Text;
 
  using XFS = MockUnixSupport;
 
- using System.Threading.Tasks;
- using System.Threading;
-
  public class MockFileReadAllLinesTests
  {
  [Test]
@@ -63,7 +63,7 @@ public void MockFile_ReadAllLines_NotExistingFile_ThrowsCorrectFileNotFoundExcep
  var mockFileSystem = new MockFileSystem();
 
  var act = new TestDelegate(() =>
- mockFileSystem.File.ReadAllText(absentFileNameFullPath)
+ mockFileSystem.File.ReadAllLines(absentFileNameFullPath)
  );
 
  var exception = Assert.Catch<FileNotFoundException>(act);
@@ -149,13 +149,95 @@ public void MockFile_ReadAllLinesAsync_NotExistingFile_ThrowsCorrectFileNotFound
  var mockFileSystem = new MockFileSystem();
 
  var act = new AsyncTestDelegate(async () =>
- await mockFileSystem.File.ReadAllTextAsync(absentFileNameFullPath)
+ await mockFileSystem.File.ReadAllLinesAsync(absentFileNameFullPath)
  );
 
  var exception = Assert.CatchAsync<FileNotFoundException>(act);
  Assert.That(exception.FileName, Is.EqualTo(absentFileNameFullPath));
  Assert.That(exception.Message, Is.EqualTo("Could not find file '" + absentFileNameFullPath + "'."));
  }
+
+#if FEATURE_READ_LINES_ASYNC
+ [Test]
+ public async Task MockFile_ReadLinesAsync_ShouldReturnOriginalTextData()
+ {
+ // Arrange
+ var fileSystem = new MockFileSystem(new Dictionary<string, MockFileData>
+ {
+ { XFS.Path(@"c:\something\demo.txt"), new MockFileData("Demo\r\ntext\ncontent\rvalue") },
+ { XFS.Path(@"c:\something\other.gif"), new MockFileData(new byte[] { 0x21, 0x58, 0x3f, 0xa9 }) }
+ });
+
+ var file = new MockFile(fileSystem);
+
+ // Act
+ var enumerable = file.ReadLinesAsync(XFS.Path(@"c:\something\demo.txt"));
+ StringCollection result = new();
+ await foreach (var line in enumerable)
+ result.Add(line);
+
+ // Assert
+ CollectionAssert.AreEqual(
+ new[] { "Demo", "text", "content", "value" },
+ result);
+ }
+
+ [Test]
+ public async Task MockFile_ReadLinesAsync_ShouldReturnOriginalDataWithCustomEncoding()
+ {
+ // Arrange
+ string text = "Hello\r\nthere\rBob\nBob!";
+ var encodedText = Encoding.BigEndianUnicode.GetBytes(text);
+ var fileSystem = new MockFileSystem(new Dictionary<string, MockFileData>
+ {
+ { XFS.Path(@"c:\something\demo.txt"), new MockFileData(encodedText) }
+ });
+
+ var file = new MockFile(fileSystem);
+
+ // Act
+ var enumerable = file.ReadLinesAsync(XFS.Path(@"c:\something\demo.txt"), Encoding.BigEndianUnicode);
+ StringCollection result = new();
+ await foreach (var line in enumerable)
+ result.Add(line);
+
+ // Assert
+ CollectionAssert.AreEqual(
+ new[] { "Hello", "there", "Bob", "Bob!" },
+ result);
+ }
+
+ [Test]
+ public void MockFile_ReadLinesAsync_ShouldThrowOperationCanceledExceptionIfCanceled()
+ {
+ var fileSystem = new MockFileSystem();
+
+ AsyncTestDelegate action = async () =>
+ {
+ var enumerable = fileSystem.File.ReadLinesAsync(@"C:\a.txt", new CancellationToken(canceled: true));
+ await foreach (var line in enumerable);
+ };
+
+ Assert.ThrowsAsync<OperationCanceledException>(action);
+ }
+
+ [Test]
+ public void MockFile_ReadLinesAsync_NotExistingFile_ThrowsCorrectFileNotFoundException()
+ {
+ var absentFileNameFullPath = XFS.Path(@"c:\you surely don't have such file.hope-so");
+ var mockFileSystem = new MockFileSystem();
+
+ AsyncTestDelegate action = async () =>
+ {
+ var enumerable = mockFileSystem.File.ReadLinesAsync(absentFileNameFullPath);
+ await foreach (var line in enumerable) ;
+ };
+
+ var exception = Assert.CatchAsync<FileNotFoundException>(action);
+ Assert.That(exception.FileName, Is.EqualTo(absentFileNameFullPath));
+ Assert.That(exception.Message, Is.EqualTo("Could not find file '" + absentFileNameFullPath + "'."));
+ }
+#endif
 #endif
  }
-}
+}