add new analyzers for StreamReader / StreamWriter (#83)

- for #81

Author: LukasGelke

System.IO.Abstractions.Analyzers.Tests/Analyzers/StreamReaderAnalyzerTests.cs

@@ -0,0 +1,50 @@
+using System.Collections.Generic;
+using System.IO.Abstractions.Analyzers.Analyzers.FileSystemTypeAnalyzers;
+using Microsoft.CodeAnalysis;
+using Roslyn.Testing.Analyzer;
+using Roslyn.Testing.Model;
+using Xunit;
+
+namespace System.IO.Abstractions.Analyzers.Tests.Analyzers
+{
+	public class StreamReaderAnalyzerTests : CSharpDiagnosticAnalyzerTest<StreamReaderAnalyzer>
+	{
+		[Theory]
+		[InlineData("UsingStream.txt")]
+		public void Analyzer_is_not_triggered(string filename)
+		{
+			var source = ReadFile(filename);
+			VerifyNoDiagnosticTriggered(source);
+		}
+
+		[Theory]
+		[InlineData("UsingFilename.txt", 15, 19)]
+		[InlineData("UsingFilenameAndOtherParameters.txt", 16, 19)]
+		public void Analyzer_is_triggered(string filename, int diagnosticLine, int diagnosticColumn)
+		{
+			var source = ReadFile(filename);
+
+			var expectedDiagnostic = new DiagnosticResult
+			{
+				Id = StreamReaderAnalyzer.DiagnosticId,
+				Message = StreamReaderAnalyzer.MessageFormat,
+				Severity = DiagnosticSeverity.Warning,
+				Locations = new[] { new DiagnosticResultLocation("Test0.cs", diagnosticLine, diagnosticColumn) }
+			};
+
+			VerifyDiagnostic(source, expectedDiagnostic);
+		}
+
+		[Fact]
+		public void Empty_source_code_does_not_trigger_analyzer()
+		{
+			var source = string.Empty;
+			VerifyNoDiagnosticTriggered(source);
+		}
+
+		protected override IEnumerable<MetadataReference> GetAdditionalReferences() => new[]
+		{
+			MetadataReference.CreateFromFile(typeof(IFileSystem).Assembly.Location)
+		};
+	}
+}

System.IO.Abstractions.Analyzers.Tests/Analyzers/StreamWriterAnalyzerTests.cs

@@ -0,0 +1,50 @@
+using System.Collections.Generic;
+using System.IO.Abstractions.Analyzers.Analyzers.FileSystemTypeAnalyzers;
+using Microsoft.CodeAnalysis;
+using Roslyn.Testing.Analyzer;
+using Roslyn.Testing.Model;
+using Xunit;
+
+namespace System.IO.Abstractions.Analyzers.Tests.Analyzers
+{
+	public class StreamWriterAnalyzerTests : CSharpDiagnosticAnalyzerTest<StreamWriterAnalyzer>
+	{
+		[Theory]
+		[InlineData("UsingStream.txt")]
+		public void Analyzer_is_not_triggered(string filename)
+		{
+			var source = ReadFile(filename);
+			VerifyNoDiagnosticTriggered(source);
+		}
+
+		[Theory]
+		[InlineData("UsingFilename.txt", 15, 19)]
+		[InlineData("UsingFilenameAndOtherParameters.txt", 16, 19)]
+		public void Analyzer_is_triggered(string filename, int diagnosticLine, int diagnosticColumn)
+		{
+			var source = ReadFile(filename);
+
+			var expectedDiagnostic = new DiagnosticResult
+			{
+				Id = StreamWriterAnalyzer.DiagnosticId,
+				Message = StreamWriterAnalyzer.MessageFormat,
+				Severity = DiagnosticSeverity.Warning,
+				Locations = new[] { new DiagnosticResultLocation("Test0.cs", diagnosticLine, diagnosticColumn) }
+			};
+
+			VerifyDiagnostic(source, expectedDiagnostic);
+		}
+
+		[Fact]
+		public void Empty_source_code_does_not_trigger_analyzer()
+		{
+			var source = string.Empty;
+			VerifyNoDiagnosticTriggered(source);
+		}
+
+		protected override IEnumerable<MetadataReference> GetAdditionalReferences() => new[]
+		{
+			MetadataReference.CreateFromFile(typeof(IFileSystem).Assembly.Location)
+		};
+	}
+}

System.IO.Abstractions.Analyzers.Tests/TestData/Analyzer/StreamReaderAnalyzer/UsingFilename.txt

@@ -0,0 +1,21 @@
+using System.IO;
+
+namespace SomeNameSpace
+{
+	public class UsingFilename
+	{
+		public UsingFilename()
+		{
+		}
+
+		public void SomeMethod()
+		{
+			const string path = "C:\\temp.txt";
+
+			using (var x = new StreamReader(path))
+			{
+				;
+			}
+		}
+	}
+}

System.IO.Abstractions.Analyzers.Tests/TestData/Analyzer/StreamReaderAnalyzer/UsingFilenameAndOtherParameters.txt

@@ -0,0 +1,22 @@
+using System.IO;
+using System.Text;
+
+namespace SomeNameSpace
+{
+	public class UsingFilenameAndOtherParameters
+	{
+		public UsingFilenameAndOtherParameters()
+		{
+		}
+
+		public void SomeMethod()
+		{
+			const string path = "C:\\temp.txt";
+
+			using (var x = new StreamReader(path, Encoding.UTF8))
+			{
+				;
+			}
+		}
+	}
+}

System.IO.Abstractions.Analyzers.Tests/TestData/Analyzer/StreamReaderAnalyzer/UsingStream.txt

@@ -0,0 +1,31 @@
+using System.IO;
+using System.IO.Abstractions;
+using System.Text;
+
+namespace SomeNameSpace
+{
+	public class UsingStream
+	{
+		private readonly IFileSystem _fileSystem;
+
+		public UsingStream(IFileSystem fileSystem)
+		{
+			_fileSystem = fileSystem;
+		}
+
+		public void SomeMethod()
+		{
+			const string path = "C:\\temp.txt";
+			var stream = _fileSystem.FileStream.Create(path, FileMode.Open);
+			using (var writer = new StreamReader(stream))
+			{
+				;
+			}
+
+			using (var writer = new StreamReader(stream, Encoding.UTF8))
+			{
+				;
+			}
+		}
+	}
+}

System.IO.Abstractions.Analyzers.Tests/TestData/Analyzer/StreamWriterAnalyzer/UsingFilename.txt

@@ -0,0 +1,21 @@
+using System.IO;
+
+namespace SomeNameSpace
+{
+	public class UsingFilename
+	{
+		public UsingFilename()
+		{
+		}
+
+		public void SomeMethod()
+		{
+			const string path = "C:\\temp.txt";
+
+			using (var x = new StreamWriter(path))
+			{
+				;
+			}
+		}
+	}
+}

System.IO.Abstractions.Analyzers.Tests/TestData/Analyzer/StreamWriterAnalyzer/UsingFilenameAndOtherParameters.txt

@@ -0,0 +1,22 @@
+using System.IO;
+using System.Text;
+
+namespace SomeNameSpace
+{
+	public class UsingFilenameAndOtherParameters
+	{
+		public UsingFilenameAndOtherParameters()
+		{
+		}
+
+		public void SomeMethod()
+		{
+			const string path = "C:\\temp.txt";
+
+			using (var x = new StreamWriter(path, true, Encoding.UTF8))
+			{
+				;
+			}
+		}
+	}
+}

System.IO.Abstractions.Analyzers.Tests/TestData/Analyzer/StreamWriterAnalyzer/UsingStream.txt

@@ -0,0 +1,31 @@
+using System.IO;
+using System.IO.Abstractions;
+using System.Text;
+
+namespace SomeNameSpace
+{
+	public class UsingStream
+	{
+		private readonly IFileSystem _fileSystem;
+
+		public UsingStream(IFileSystem fileSystem)
+		{
+			_fileSystem = fileSystem;
+		}
+
+		public void SomeMethod()
+		{
+			const string path = "C:\\temp.txt";
+			var stream = _fileSystem.FileStream.Create(path, FileMode.Open);
+			using (var writer = new StreamWriter(stream))
+			{
+				;
+			}
+
+			using (var writer = new StreamWriter(stream, true, Encoding.UTF8))
+			{
+				;
+			}
+		}
+	}
+}

System.IO.Abstractions.Analyzers/Analyzers/BaseFileSystemNodeAnalyzer.cs

@@ -95,5 +95,13 @@ INamespaceSymbol namespaceSymbol
 				&& !namespaceSymbol.IsGlobalNamespace
 				&& namespaceSymbol.ToString().StartsWith(Constants.FileSystemNameSpace, StringComparison.Ordinal);
 		}
+
+		protected static bool IsFirstConstructorParameterOfType<T>(SyntaxNodeAnalysisContext context, ExpressionSyntax syntax)
+		{
+			return (syntax as ObjectCreationExpressionSyntax)?.ArgumentList?.Arguments.FirstOrDefault() is ArgumentSyntax firstArgument
+				&& (context.SemanticModel.GetSymbolInfo(firstArgument.Expression).Symbol as ILocalSymbol)?.Type is ITypeSymbol argumentType
+				&& argumentType.ContainingNamespace.Name == typeof(T).Namespace
+				&& argumentType.Name == typeof(T).Name;
+		}
 	}
 }

System.IO.Abstractions.Analyzers/Analyzers/FileSystemTypeAnalyzers/StreamReaderAnalyzer.cs

@@ -0,0 +1,61 @@
+using System.Collections.Immutable;
+using JetBrains.Annotations;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace System.IO.Abstractions.Analyzers.Analyzers.FileSystemTypeAnalyzers
+{
+	[DiagnosticAnalyzer(LanguageNames.CSharp)]
+	public class StreamReaderAnalyzer : BaseFileSystemNodeAnalyzer
+	{
+		/// <summary>
+		/// Diagnostic Identifier
+		/// </summary>
+		[UsedImplicitly]
+		public const string DiagnosticId = "IO0011";
+
+		/// <summary>
+		/// Diagnostic Title
+		/// </summary>
+		private const string Title = "Replace StreamReader string constructor overload with stream based overload"
+			+ " using a stream from IFileSystem.FileStream for improved testability";
+
+		/// <summary>
+		/// Diagnostic Message Format
+		/// </summary>
+		public const string MessageFormat = Title;
+
+		/// <summary>
+		/// Diagnostic Description
+		/// </summary>
+		private const string Description = Title;
+
+		/// <summary>
+		/// Правило
+		/// </summary>
+		private static readonly DiagnosticDescriptor Rule = new DiagnosticDescriptor(DiagnosticId,
+			Title,
+			MessageFormat,
+			Category,
+			DiagnosticSeverity.Warning,
+			true,
+			Description);
+
+		/// <inheritdoc />
+		public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => ImmutableArray.Create(Rule);
+
+		/// <inheritdoc />
+		protected override void Analyze(SyntaxNodeAnalysisContext context, ExpressionSyntax syntax)
+		{
+			if (IsFirstConstructorParameterOfType<string>(context, syntax))
+				context.ReportDiagnostic(Diagnostic.Create(Rule, syntax.GetLocation()));
+		}
+
+		/// <inheritdoc />
+		protected override Type GetFileSystemType()
+		{
+			return typeof(StreamReader);
+		}
+	}
+}