Add test for formatting code fix relying on .editorconfig

src/CodeStyle/CSharp/CodeFixes/CSharpFormattingCodeFixProvider.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Composition;
+using Microsoft.CodeAnalysis.CodeFixes;
+using Microsoft.CodeAnalysis.Options;
+using Microsoft.VisualStudio.CodingConventions;
+
+namespace Microsoft.CodeAnalysis.CodeStyle
+{
+    [ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.FixFormatting)]
+    [Shared]
+    internal class CSharpFormattingCodeFixProvider : AbstractFormattingCodeFixProvider
+    {
+        private readonly EditorConfigOptionsApplier _editorConfigOptionsApplier = new EditorConfigOptionsApplier();
+
+        protected override OptionSet ApplyFormattingOptions(OptionSet optionSet, ICodingConventionContext codingConventionContext)
+        {
+            return _editorConfigOptionsApplier.ApplyConventions(optionSet, codingConventionContext.CurrentConventions, LanguageNames.CSharp);
+        }
+    }
+}

src/CodeStyle/CSharp/Tests/FormattingAnalyzerTests.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.IO;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CSharp.Testing;
 using Microsoft.CodeAnalysis.Testing.Verifiers;
@@ -7,7 +8,7 @@
 
 namespace Microsoft.CodeAnalysis.CodeStyle
 {
-    using Verify = CSharpCodeFixVerifier<CSharpFormattingAnalyzer, FormattingCodeFixProvider, XUnitVerifier>;
+    using Verify = CSharpCodeFixVerifier<CSharpFormattingAnalyzer, CSharpFormattingCodeFixProvider, XUnitVerifier>;
 
     public class FormattingAnalyzerTests
     {
@@ -184,7 +185,7 @@ class MyClass
 }
 ";
 
-            await new CSharpCodeFixTest<CSharpFormattingAnalyzer, FormattingCodeFixProvider, XUnitVerifier>
+            await new CSharpCodeFixTest<CSharpFormattingAnalyzer, CSharpFormattingCodeFixProvider, XUnitVerifier>
             {
                 TestCode = testCode,
                 FixedCode = fixedCode,
@@ -194,5 +195,50 @@ class MyClass
                 NumberOfIncrementalIterations = 2,
             }.RunAsync();
         }
+
+        [Fact]
+        public async Task TestEditorConfigUsed()
+        {
+            var testCode = @"
+class MyClass {
+    void MyMethod()[| |]{
+    }
+}
+";
+            var fixedCode = @"
+class MyClass {
+    void MyMethod()
+    {
+    }
+}
+";
+            var editorConfig = @"
+root = true
+
+[*.cs]
+csharp_new_line_before_open_brace = methods
+";
+
+            var testDirectoryName = Path.GetRandomFileName();
+            Directory.CreateDirectory(testDirectoryName);
+            try
+            {
+                File.WriteAllText(Path.Combine(testDirectoryName, ".editorconfig"), editorConfig);
+
+                // The contents of this file are ignored, but the coding conventions library checks for existence before
+                // .editorconfig is used.
+                File.WriteAllText(Path.Combine(testDirectoryName, "Test0.cs"), string.Empty);
+
+                await new CSharpCodeFixTest<CSharpFormattingAnalyzer, CSharpFormattingCodeFixProvider, XUnitVerifier>
+                {
+                    TestState = { Sources = { (Path.GetFullPath(Path.Combine(testDirectoryName, "Test0.cs")), testCode) } },
+                    FixedState = { Sources = { (Path.GetFullPath(Path.Combine(testDirectoryName, "Test0.cs")), fixedCode) } },
+                }.RunAsync();
+            }
+            finally
+            {
+                Directory.Delete(testDirectoryName, true);
+            }
+        }
     }
 }

src/CodeStyle/Core/CodeFixes/FormattingCodeFixHelper.cs

@@ -3,13 +3,14 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Formatting;
+using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.Text;
 
 namespace Microsoft.CodeAnalysis
 {
     internal static class FormattingCodeFixHelper
     {
-        internal static async Task<Document> FixOneAsync(Document document, Diagnostic diagnostic, CancellationToken cancellationToken)
+        internal static async Task<Document> FixOneAsync(Document document, OptionSet options, Diagnostic diagnostic, CancellationToken cancellationToken)
         {
             var tree = await document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
 
@@ -21,7 +22,6 @@ internal static async Task<Document> FixOneAsync(Document document, Diagnostic d
                 text.Lines[diagnosticLinePositionSpan.Start.Line].Start,
                 text.Lines[diagnosticLinePositionSpan.End.Line].End);
 
-            var options = await document.GetOptionsAsync(cancellationToken).ConfigureAwait(false);
             return await Formatter.FormatAsync(document, spanToFormat, options, cancellationToken).ConfigureAwait(false);
         }
     }

src/CodeStyle/Core/CodeFixes/FormattingCodeFixProvider.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System.Collections.Immutable;
-using System.Composition;
+using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Formatting;
+using Microsoft.CodeAnalysis.Options;
+using Microsoft.VisualStudio.CodingConventions;
 
 namespace Microsoft.CodeAnalysis.CodeStyle
 {
-    [ExportCodeFixProvider(LanguageNames.CSharp, LanguageNames.VisualBasic, Name = PredefinedCodeFixProviderNames.FixFormatting)]
-    [Shared]
-    internal class FormattingCodeFixProvider : CodeFixProvider
+    internal abstract class AbstractFormattingCodeFixProvider : CodeFixProvider
     {
-        public override ImmutableArray<string> FixableDiagnosticIds
+        public sealed override ImmutableArray<string> FixableDiagnosticIds
             => ImmutableArray.Create(IDEDiagnosticIds.FormattingDiagnosticId);
 
-        public override FixAllProvider GetFixAllProvider()
+        public sealed override FixAllProvider GetFixAllProvider()
         {
-            return new FixAll();
+            return new FixAll(this);
         }
 
-        public override Task RegisterCodeFixesAsync(CodeFixContext context)
+        public sealed override Task RegisterCodeFixesAsync(CodeFixContext context)
         {
             foreach (var diagnostic in context.Diagnostics)
             {
                 context.RegisterCodeFix(
                     CodeAction.Create(
                         CodeStyleResources.Fix_formatting,
-                        c => FormattingCodeFixHelper.FixOneAsync(context.Document, diagnostic, c),
-                        nameof(FormattingCodeFixProvider)),
+                        c => FixOneAsync(context, diagnostic, c),
+                        nameof(AbstractFormattingCodeFixProvider)),
                     diagnostic);
             }
 
             return Task.CompletedTask;
         }
 
+        protected abstract OptionSet ApplyFormattingOptions(OptionSet optionSet, ICodingConventionContext codingConventionContext);
+
+        private async Task<Document> FixOneAsync(CodeFixContext context, Diagnostic diagnostic, CancellationToken cancellationToken)
+        {
+            var options = await GetOptionsAsync(context.Document, cancellationToken).ConfigureAwait(false);
+            return await FormattingCodeFixHelper.FixOneAsync(context.Document, options, diagnostic, cancellationToken).ConfigureAwait(false);
+        }
+
+        private async Task<OptionSet> GetOptionsAsync(Document document, CancellationToken cancellationToken)
+        {
+            OptionSet options = await document.GetOptionsAsync(cancellationToken).ConfigureAwait(false);
+
+            // The in-IDE workspace supports .editorconfig without special handling. However, the AdhocWorkspace used
+            // in testing requires manual handling of .editorconfig.
+            if (document.Project.Solution.Workspace is AdhocWorkspace && File.Exists(document.FilePath ?? document.Name))
+            {
+                var codingConventionsManager = CodingConventionsManagerFactory.CreateCodingConventionsManager();
+                var codingConventionContext = await codingConventionsManager.GetConventionContextAsync(document.FilePath ?? document.Name, cancellationToken).ConfigureAwait(false);
+                options = ApplyFormattingOptions(options, codingConventionContext);
+            }
+
+            return options;
+        }
+
         /// <summary>
         /// Provide an optimized Fix All implementation that runs
         /// <see cref="Formatter.FormatAsync(Document, Options.OptionSet, CancellationToken)"/> on the document(s)
@@ -45,11 +69,18 @@ public override Task RegisterCodeFixesAsync(CodeFixContext context)
         /// </summary>
         private class FixAll : DocumentBasedFixAllProvider
         {
+            private readonly AbstractFormattingCodeFixProvider _formattingCodeFixProvider;
+
+            public FixAll(AbstractFormattingCodeFixProvider formattingCodeFixProvider)
+            {
+                _formattingCodeFixProvider = formattingCodeFixProvider;
+            }
+
             protected override string CodeActionTitle => CodeStyleResources.Fix_formatting;
 
             protected override async Task<SyntaxNode> FixAllInDocumentAsync(FixAllContext fixAllContext, Document document, ImmutableArray<Diagnostic> diagnostics)
             {
-                var options = await document.GetOptionsAsync(fixAllContext.CancellationToken).ConfigureAwait(false);
+                var options = await _formattingCodeFixProvider.GetOptionsAsync(document, fixAllContext.CancellationToken).ConfigureAwait(false);
                 var updatedDocument = await Formatter.FormatAsync(document, options, fixAllContext.CancellationToken).ConfigureAwait(false);
                 return await updatedDocument.GetSyntaxRootAsync(fixAllContext.CancellationToken).ConfigureAwait(false);
             }

src/CodeStyle/VisualBasic/CodeFixes/VisualBasicFormattingCodeFixProvider.vb

+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Composition
+Imports Microsoft.CodeAnalysis.CodeFixes
+Imports Microsoft.CodeAnalysis.Options
+Imports Microsoft.VisualStudio.CodingConventions
+
+Namespace Microsoft.CodeAnalysis.CodeStyle
+    <ExportCodeFixProvider(LanguageNames.VisualBasic, Name:=PredefinedCodeFixProviderNames.FixFormatting)>
+    <[Shared]>
+    Friend Class VisualBasicFormattingCodeFixProvider
+        Inherits AbstractFormattingCodeFixProvider
+
+        Protected Overrides Function ApplyFormattingOptions(optionSet As OptionSet, codingConventionContext As ICodingConventionContext) As OptionSet
+            Return optionSet
+        End Function
+    End Class
+End Namespace
+

src/CodeStyle/VisualBasic/Tests/FormattingAnalyzerTests.vb

@@ -3,7 +3,7 @@
 Imports Xunit
 Imports VerifyVB = Microsoft.CodeAnalysis.VisualBasic.Testing.VisualBasicCodeFixVerifier(
     Of Microsoft.CodeAnalysis.CodeStyle.VisualBasicFormattingAnalyzer,
-    Microsoft.CodeAnalysis.CodeStyle.FormattingCodeFixProvider,
+    Microsoft.CodeAnalysis.CodeStyle.VisualBasicFormattingCodeFixProvider,
     Microsoft.CodeAnalysis.Testing.Verifiers.XUnitVerifier)
 
 Namespace Microsoft.CodeAnalysis.CodeStyle

src/Features/Core/Portable/Formatting/FormattingCodeFixProvider.cs

@@ -24,13 +24,19 @@ public override Task RegisterCodeFixesAsync(CodeFixContext context)
             foreach (var diagnostic in context.Diagnostics)
             {
                 context.RegisterCodeFix(
-                    new MyCodeAction(c => FormattingCodeFixHelper.FixOneAsync(context.Document, diagnostic, c)),
+                    new MyCodeAction(c => FixOneAsync(context, diagnostic, c)),
                     diagnostic);
             }
 
             return Task.CompletedTask;
         }
 
+        private static async Task<Document> FixOneAsync(CodeFixContext context, Diagnostic diagnostic, CancellationToken cancellationToken)
+        {
+            var options = await context.Document.GetOptionsAsync(cancellationToken).ConfigureAwait(false);
+            return await FormattingCodeFixHelper.FixOneAsync(context.Document, options, diagnostic, cancellationToken).ConfigureAwait(false);
+        }
+
         protected override async Task FixAllAsync(Document document, ImmutableArray<Diagnostic> diagnostics, SyntaxEditor editor, CancellationToken cancellationToken)
         {
             var options = await document.GetOptionsAsync(cancellationToken).ConfigureAwait(false);