feat: Added ConfigFile to simplify AnalyzerConfigFile creation.

src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/ConfigFile.cs

@@ -0,0 +1,48 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Microsoft.CodeAnalysis.Testing
+{
+    public class ConfigFile
+    {
+        public Dictionary<string, string> Preamble { get; }
+
+        public Dictionary<string, Dictionary<string, string>> Sections { get; }
+
+        public ConfigFile(
+            Dictionary<string, string>? preamble = null,
+            Dictionary<string, Dictionary<string, string>>? sections = null)
+        {
+            Preamble = preamble ?? new Dictionary<string, string>();
+            Sections = sections ?? new Dictionary<string, Dictionary<string, string>>();
+        }
+
+        private static string ToString(Dictionary<string, string> dictionary)
+        {
+            return string.Join(
+                Environment.NewLine,
+                dictionary.Select(pair => $@"{pair.Key} = {pair.Value}"));
+        }
+
+        private static string ToString(Dictionary<string, Dictionary<string, string>> dictionary)
+        {
+            return string.Join(
+                Environment.NewLine,
+                dictionary.Select(pair => $@"[{pair.Key}]
+{ToString(pair.Value)}"));
+        }
+
+        public override string ToString()
+        {
+            return @$"
+{ToString(Preamble)}
+
+{ToString(Sections)}";
+        }
+    }
+}

src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/PublicAPI.Unshipped.txt

@@ -49,6 +49,10 @@ Microsoft.CodeAnalysis.Testing.CompilerDiagnostics.Errors = 1 -> Microsoft.CodeA
 Microsoft.CodeAnalysis.Testing.CompilerDiagnostics.None = 0 -> Microsoft.CodeAnalysis.Testing.CompilerDiagnostics
 Microsoft.CodeAnalysis.Testing.CompilerDiagnostics.Suggestions = 3 -> Microsoft.CodeAnalysis.Testing.CompilerDiagnostics
 Microsoft.CodeAnalysis.Testing.CompilerDiagnostics.Warnings = 2 -> Microsoft.CodeAnalysis.Testing.CompilerDiagnostics
+Microsoft.CodeAnalysis.Testing.ConfigFile
+Microsoft.CodeAnalysis.Testing.ConfigFile.ConfigFile(System.Collections.Generic.Dictionary<string, string> preamble = null, System.Collections.Generic.Dictionary<string, System.Collections.Generic.Dictionary<string, string>> sections = null) -> void
+Microsoft.CodeAnalysis.Testing.ConfigFile.Preamble.get -> System.Collections.Generic.Dictionary<string, string>
+Microsoft.CodeAnalysis.Testing.ConfigFile.Sections.get -> System.Collections.Generic.Dictionary<string, System.Collections.Generic.Dictionary<string, string>>
 Microsoft.CodeAnalysis.Testing.DefaultVerifier
 Microsoft.CodeAnalysis.Testing.DefaultVerifier.Context.get -> System.Collections.Immutable.ImmutableStack<string>
 Microsoft.CodeAnalysis.Testing.DefaultVerifier.DefaultVerifier() -> void
@@ -218,6 +222,7 @@ Microsoft.CodeAnalysis.Testing.SolutionState.WithProcessedMarkup(Microsoft.CodeA
 Microsoft.CodeAnalysis.Testing.SourceFileCollection
 Microsoft.CodeAnalysis.Testing.SourceFileCollection.Add((System.Type sourceGeneratorType, string filename, Microsoft.CodeAnalysis.Text.SourceText content) file) -> void
 Microsoft.CodeAnalysis.Testing.SourceFileCollection.Add((System.Type sourceGeneratorType, string filename, string content) file) -> void
+Microsoft.CodeAnalysis.Testing.SourceFileCollection.Add((string filename, Microsoft.CodeAnalysis.Testing.ConfigFile configFile) file) -> void
 Microsoft.CodeAnalysis.Testing.SourceFileCollection.Add((string filename, string content) file) -> void
 Microsoft.CodeAnalysis.Testing.SourceFileCollection.SourceFileCollection() -> void
 Microsoft.CodeAnalysis.Testing.SourceFileList
@@ -240,6 +245,7 @@ abstract Microsoft.CodeAnalysis.Testing.AnalyzerTest<TVerifier>.DefaultFileExt.g
 abstract Microsoft.CodeAnalysis.Testing.AnalyzerTest<TVerifier>.GetDiagnosticAnalyzers() -> System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer>
 abstract Microsoft.CodeAnalysis.Testing.AnalyzerTest<TVerifier>.Language.get -> string
 abstract Microsoft.CodeAnalysis.Testing.CodeActionTest<TVerifier>.SyntaxKindType.get -> System.Type
+override Microsoft.CodeAnalysis.Testing.ConfigFile.ToString() -> string
 override Microsoft.CodeAnalysis.Testing.DiagnosticResult.ToString() -> string
 override Microsoft.CodeAnalysis.Testing.EmptyDiagnosticAnalyzer.Initialize(Microsoft.CodeAnalysis.Diagnostics.AnalysisContext context) -> void
 override Microsoft.CodeAnalysis.Testing.EmptyDiagnosticAnalyzer.SupportedDiagnostics.get -> System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.DiagnosticDescriptor>

src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/SourceFileCollection.cs

@@ -29,5 +29,10 @@ public void Add((Type sourceGeneratorType, string filename, SourceText content)
             var generatedPath = Path.Combine(file.sourceGeneratorType.GetTypeInfo().Assembly.GetName().Name ?? string.Empty, file.sourceGeneratorType.FullName!, file.filename);
             Add((generatedPath, file.content));
         }
+
+        public void Add((string filename, ConfigFile configFile) file)
+        {
+            Add((file.filename, SourceText.From(file.configFile.ToString(), Encoding.UTF8)));
+        }
     }
 }

tests/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing.UnitTests/AnalyzerConfigFilesTests.cs

@@ -5,6 +5,7 @@
 #if !NETCOREAPP1_1 && !NET46
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Text;
 using System.Threading.Tasks;
@@ -119,6 +120,32 @@ public async Task TestDiagnosticInAnalyzerConfigFileBraceNotTreatedAsMarkup()
             }.RunAsync();
         }
 
+        [Fact]
+        public void AnalyzerConfigFileEquivalentToManualCreation()
+        {
+            var expected = @"
+root = true
+
+[*]
+key = {|Literal:value|}
+";
+
+            var actual = new ConfigFile(
+                preamble: new Dictionary<string, string>
+                {
+                    ["root"] = "true",
+                },
+                sections: new Dictionary<string, Dictionary<string, string>>
+                {
+                    ["*"] = new Dictionary<string, string>
+                    {
+                        ["key"] = "{|Literal:value|}",
+                    },
+                }).ToString();
+
+            Assert.Equal(expected, actual);
+        }
+
         [DiagnosticAnalyzer(LanguageNames.CSharp)]
         internal class HighlightBracesIfAnalyzerConfigMissingAnalyzer : DiagnosticAnalyzer
         {