feat: added snapshot testing for generated code

Refit.Tests/InterfaceStubGenerator.cs

@@ -1,10 +1,5 @@
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.IO;
-using System.Linq;
+using System.Collections.Immutable;
 using System.Reflection;
-using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.Testing;

Refit.sln

@@ -34,6 +34,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Refit.Xml", "Refit.Xml\Refi
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Refit.Benchmarks", "Refit.Benchmarks\Refit.Benchmarks.csproj", "{ABD72A27-9C30-481A-8303-D8F825A8FD47}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "RefitGenerator.Tests", "RefitGenerator.Tests\RefitGenerator.Tests.csproj", "{10790A5E-8FB6-451B-BCBC-8F641973F22C}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -174,13 +176,30 @@ Global
 		{ABD72A27-9C30-481A-8303-D8F825A8FD47}.Release|x64.Build.0 = Release|Any CPU
 		{ABD72A27-9C30-481A-8303-D8F825A8FD47}.Release|x86.ActiveCfg = Release|Any CPU
 		{ABD72A27-9C30-481A-8303-D8F825A8FD47}.Release|x86.Build.0 = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|ARM.ActiveCfg = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|ARM.Build.0 = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|x64.Build.0 = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Debug|x86.Build.0 = Debug|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|ARM.ActiveCfg = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|ARM.Build.0 = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|x64.ActiveCfg = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|x64.Build.0 = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|x86.ActiveCfg = Release|Any CPU
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{EB833B36-D3CA-4308-A776-8D574F2ADF64} = {0E99249A-FB80-4C60-8FD3-13820E853FF7}
 		{ABD72A27-9C30-481A-8303-D8F825A8FD47} = {0E99249A-FB80-4C60-8FD3-13820E853FF7}
+		{10790A5E-8FB6-451B-BCBC-8F641973F22C} = {0E99249A-FB80-4C60-8FD3-13820E853FF7}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {6E9C2873-AFF9-4D32-A784-1BA094814054}

RefitGenerator.Tests/BaseTestClass.cs

@@ -0,0 +1,16 @@
+using System.Runtime.CompilerServices;
+
+namespace RefitGenerator.Tests;
+
+public class BaseTestClass
+{
+    static BaseTestClass()
+    {
+        Verifier.DerivePathInfo(
+            (file, _, type, method) => new(Path.Combine(Path.GetDirectoryName(file), "_snapshots"), type.Name, method.Name)
+        );
+
+        VerifySourceGenerators.Initialize();
+        VerifyDiffPlex.Initialize(VerifyTests.DiffPlex.OutputType.Compact);
+    }
+}

RefitGenerator.Tests/Fixture.cs

@@ -0,0 +1,108 @@
+using System.Net.Http;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+
+using Refit;
+using Refit.Generator;
+
+namespace RefitGenerator.Tests;
+
+
+public static class Fixture
+{
+    private const string MainTestFile = "Refit.Tests";
+
+    static readonly MetadataReference RefitAssembly = MetadataReference.CreateFromFile(
+        typeof(GetAttribute).Assembly.Location,
+        documentation: XmlDocumentationProvider.CreateFromFile(
+            Path.ChangeExtension(typeof(GetAttribute).Assembly.Location, ".xml")
+        )
+    );
+
+    private static readonly Type[] ImportantAssemblies = new[]
+    {
+        typeof(Binder),
+        typeof(GetAttribute),
+        typeof(System.Reactive.Unit),
+        typeof(Enumerable),
+        typeof(Newtonsoft.Json.JsonConvert),
+        typeof(FactAttribute),
+        typeof(HttpContent),
+        // typeof(ModelObject),
+        typeof(Attribute)
+    };
+
+    public static Assembly[] AssemblyReferencesForCodegen =>
+        AppDomain.CurrentDomain
+            .GetAssemblies()
+            .Concat(ImportantAssemblies.Select(x=>x.Assembly))
+            .Distinct()
+            .Where(a => !a.IsDynamic)
+            .ToArray();
+
+    public static Compilation CreateLibrary(params string[] source)
+    {
+        var references = new List<MetadataReference>();
+        var assemblies = AssemblyReferencesForCodegen;
+        foreach (var assembly in assemblies)
+        {
+            if (!assembly.IsDynamic)
+            {
+                references.Add(MetadataReference.CreateFromFile(assembly.Location));
+            }
+        }
+
+        references.Add(RefitAssembly);
+        var compilation = CSharpCompilation.Create(
+            "compilation",
+            source.Select(s => CSharpSyntaxTree.ParseText(s)),
+            references,
+            new CSharpCompilationOptions(OutputKind.ConsoleApplication)
+        );
+
+        return compilation;
+    }
+
+    public static Task VerifyGenerator(string source)
+    {
+        var compilation = CreateLibrary(source);
+
+        var generator = new InterfaceStubGenerator();
+        var driver = CSharpGeneratorDriver.Create(generator);
+
+        var ranDriver = driver.RunGenerators(compilation);
+        var verify = VerifyXunit.Verifier.Verify(ranDriver);
+        return verify.ToTask();
+    }
+
+    public static async Task<string> GetFileFromRefitTest(string file)
+    {
+#if NET481
+        return File.ReadAllText(GetRefitTestPath(file));
+#else
+        return await File.ReadAllTextAsync(GetRefitTestPath(file)).ConfigureAwait(false);
+#endif
+    }
+
+    private static string GetRefitTestPath(params string[] paths)
+    {
+        var ret = GetIntegrationTestRootDirectory();
+        var start = ret.Split('\\');
+        // ReSharper disable once UseIndexFromEndExpression
+        start[start.Length - 1] = MainTestFile;
+        ret = string.Join("\\", start);
+        return (new FileInfo(paths.Aggregate(ret, Path.Combine))).FullName;
+    }
+
+    private static string GetIntegrationTestRootDirectory([CallerFilePath] string filePath = default)
+    {
+        // XXX: This is an evil hack, but it's okay for a unit test
+        // We can't use Assembly.Location because unit test runners love
+        // to move stuff to temp directories
+        var di = new DirectoryInfo(Path.Combine(Path.GetDirectoryName(filePath)));
+
+        return di.FullName;
+    }
+}

RefitGenerator.Tests/RefitGenerator.Tests.csproj

@@ -0,0 +1,46 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <Import Project="..\Refit\targets\refit.props" />
+
+    <PropertyGroup>
+        <TargetFrameworks>net481;net6.0;net8.0</TargetFrameworks>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+
+        <IsPackable>false</IsPackable>
+        <IsTestProject>true</IsTestProject>
+        <NoWarn>$(NoWarn);CS1591;CA1819;CA2000;CA2007;CA1056;CA1707;CA1861;xUnit1031</NoWarn>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="coverlet.collector" Version="6.0.0"/>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0"/>
+        <PackageReference Include="xunit" Version="2.5.3"/>
+        <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3"/>
+        <PackageReference Include="System.Collections.Immutable" Version="9.0.0-preview.5.24306.7" />
+        <PackageReference Include="Verify.DiffPlex" Version="2.3.0" />
+        <PackageReference Include="Verify.SourceGenerators" Version="2.2.0" />
+        <PackageReference Include="Verify.Xunit" Version="22.1.4" />
+        <PackageReference Include="System.Reactive" Version="6.0.1" />
+        <PackageReference Include="Microsoft.AspNetCore.WebUtilities" Version="2.2.0" />
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.9.2" />
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing" Version="1.1.2-beta1.24314.1" />
+        <ProjectReference Include="..\Refit.Newtonsoft.Json\Refit.Newtonsoft.Json.csproj" />
+        <ProjectReference Include="..\Refit.Xml\Refit.Xml.csproj" />
+      <ProjectReference Include="..\InterfaceStubGenerator.Roslyn38\InterfaceStubGenerator.Roslyn38.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="true" />
+        <ProjectReference Include="..\InterfaceStubGenerator.Roslyn40\InterfaceStubGenerator.Roslyn40.csproj" />
+        <ProjectReference Include="..\Refit\Refit.csproj" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <None Include="..\RefitGenerator.Tests\_snapshots\**">
+        <Link>%(RecursiveDir)\resources\%(Filename)%(Extension)</Link>
+        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+      </None>
+        <Using Include="Xunit"/>
+    </ItemGroup>
+
+    <ItemGroup>
+      <Folder Include="_snapshots\" />
+    </ItemGroup>
+</Project>

RefitGenerator.Tests/RefitGeneratorTests.cs

@@ -0,0 +1,26 @@
+namespace RefitGenerator.Tests;
+
+[UsesVerify]
+public class RefitGeneratorTests : BaseTestClass
+{
+    [Fact]
+    public async Task NoRefitInterfacesSmokeTest()
+    {
+        var input = await Fixture.GetFileFromRefitTest("IInterfaceWithoutRefit.cs");
+        await Fixture.VerifyGenerator(input);
+    }
+
+    [Fact]
+    public async Task FindInterfacesSmokeTest()
+    {
+        var input = await Fixture.GetFileFromRefitTest("GitHubApi.cs");
+        await Fixture.VerifyGenerator(input);
+    }
+
+    [Fact]
+    public async Task GenerateInterfaceStubsWithoutNamespaceSmokeTest()
+    {
+        var input = await Fixture.GetFileFromRefitTest("IServiceWithoutNamespace.cs");
+        await Fixture.VerifyGenerator(input);
+    }
+}

RefitGenerator.Tests/_snapshots/RefitGeneratorTests.FindInterfacesSmokeTest#Generated.g.verified.cs

@@ -0,0 +1,24 @@
+//HintName: Generated.g.cs
+
+#pragma warning disable
+namespace Refit.Implementation
+{
+
+    /// <inheritdoc />
+    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    [global::System.Diagnostics.DebuggerNonUserCode]
+    [global::RefitInternalGenerated.PreserveAttribute]
+    [global::System.Reflection.Obfuscation(Exclude=true)]
+    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+    internal static partial class Generated
+    {
+#if NET5_0_OR_GREATER
+        [System.Runtime.CompilerServices.ModuleInitializer]
+        [System.Diagnostics.CodeAnalysis.DynamicDependency(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.All, typeof(global::Refit.Implementation.Generated))]
+        public static void Initialize()
+        {
+        }
+#endif
+    }
+}
+#pragma warning restore