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Merged
jscarle merged 2 commits into from
Jun 20, 2026
Merged

Added support for enumerable sources. #26

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dd5a4df
Changed base target frameworks.
jscarle Jun 20, 2026
1060b3d
Added support for enumerable sources.
jscarle Jun 20, 2026
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40 changes: 32 additions & 8 deletions README.md
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Expand Up @@ -9,13 +9,37 @@ Test helpers and extension methods to simplify testing of .NET source generators
## Testing a source generator

```csharp
var result = SourceGenerator.Run<YourSourceGenerator>("your source");
var (generator, result) = SourceGenerator.Run<YourSourceGenerator>("your source");
```

You can also run a generator against multiple source files by passing any `IEnumerable<string>`.

```csharp
var sources = new[]
{
"namespace Tests; public partial class First;",
"namespace Tests; public partial class Second;"
};

var (generator, result) = SourceGenerator.Run<YourSourceGenerator>(sources);
```

## Testing an incremental source generator

```csharp
var result = IncrementalGenerator.Run<YourSourceGenerator>("your source");
var (generator, result) = IncrementalGenerator.Run<YourSourceGenerator>("your source");
```

The same multiple-source overload is available for incremental generators.

```csharp
var sources = new[]
{
"namespace Tests; public partial class First;",
"namespace Tests; public partial class Second;"
};

var (generator, result) = IncrementalGenerator.Run<YourSourceGenerator>(sources);
```

## Obtaining the generated source
Expand Down Expand Up @@ -50,15 +74,15 @@ Using one of the testing framework packages below, you can also assert the diffe
[![MSTest](https://img.shields.io/nuget/dt/SourceGeneratorTestHelpers.MSTest?label=MSTest)](https://www.nuget.org/packages/SourceGeneratorTestHelpers.MSTest)

```csharp
var result = IncrementalGenerator.Run<YourSourceGenerator>("your source");
var (_, result) = IncrementalGenerator.Run<YourSourceGenerator>("your source");

result.ShouldProduce("TestId.g.cs", "expected source");
```

_Note: If you do not wish to assert on errors produced during diagnostics of the source generator run, you can simply disable them as such._

```csharp
var result = IncrementalGenerator.Run<YourSourceGenerator>("your source");
var (_, result) = IncrementalGenerator.Run<YourSourceGenerator>("your source");

result.ShouldProduce("TestId.g.cs", "expected source", false);
```
Expand All @@ -75,7 +99,7 @@ public class SourceGeneratorTests
[Fact]
public Task ShouldProductTestId()
{
var result = IncrementalGenerator.Run<YourSourceGenerator>("your source");
var (_, result) = IncrementalGenerator.Run<YourSourceGenerator>("your source");
return result.VerifyAsync("TestId.g.cs");
}
}
Expand All @@ -90,7 +114,7 @@ public class SourceGeneratorTests
[Test]
public Task ShouldProductTestId()
{
var result = IncrementalGenerator.Run<YourSourceGenerator>("your source");
var (_, result) = IncrementalGenerator.Run<YourSourceGenerator>("your source");
return result.VerifyAsync("TestId.g.cs");
}
}
Expand All @@ -106,8 +130,8 @@ public class SourceGeneratorTests :
[TestMethod]
public Task ShouldProductTestId()
{
var result = IncrementalGenerator.Run<YourSourceGenerator>("your source");
return VerifyAsync("TestId.g.cs");
var (_, result) = IncrementalGenerator.Run<YourSourceGenerator>("your source");
return VerifyAsync(result, "TestId.g.cs");
}
}
```
2 changes: 1 addition & 1 deletion src/SourceGeneratorTestHelpers.MSTest/GeneratorDriverTestBase.cs
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Expand Up @@ -5,7 +5,7 @@

namespace SourceGeneratorTestHelpers.MSTest;

internal abstract class GeneratorDriverTestBase : VerifyBase
public abstract class GeneratorDriverTestBase : VerifyBase
{
/// <summary>Verifies that the generated source from a <see cref="GeneratorDriverRunResult"/> with a specific file path ending matches the expected source.</summary>
/// <param name="result">The <see cref="GeneratorDriverRunResult"/> to get the source from.</param>
Expand Down
32 changes: 24 additions & 8 deletions src/SourceGeneratorTestHelpers/Common/Helpers.cs
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Expand Up @@ -22,9 +22,10 @@ internal static (ImmutableArray<Diagnostic> CompilationDiagnostics, GeneratorDri
CSharpCompilationOptions? cSharpCompilationOptions
)
{
var sources = new[] { source };
cSharpParseOptions ??= DefaultCSharpParseOptions;
var syntaxTrees = new[] { CSharpSyntaxTree.ParseText(source, cSharpParseOptions, encoding: Encoding.UTF8) };

return InternalRunGenerator(generator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);
return InternalRunGenerator(generator, syntaxTrees, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);
}

internal static (ImmutableArray<Diagnostic> CompilationDiagnostics, GeneratorDriverRunResult Result) InternalRunGenerator(
Expand All @@ -35,8 +36,20 @@ internal static (ImmutableArray<Diagnostic> CompilationDiagnostics, GeneratorDri
CSharpCompilationOptions? cSharpCompilationOptions
)
{
var syntaxTrees = sources.Select(source => CSharpSyntaxTree.ParseText(source, cSharpParseOptions, encoding: Encoding.UTF8)).ToArray();
cSharpParseOptions ??= DefaultCSharpParseOptions;
var syntaxTrees = sources.Select(source => CSharpSyntaxTree.ParseText(source, cSharpParseOptions, encoding: Encoding.UTF8)).ToArray();

return InternalRunGenerator(generator, syntaxTrees, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);
}

private static (ImmutableArray<Diagnostic> CompilationDiagnostics, GeneratorDriverRunResult Result) InternalRunGenerator(
ISourceGenerator generator,
SyntaxTree[] syntaxTrees,
CSharpParseOptions cSharpParseOptions,
IEnumerable<MetadataReference>? metadataReferences,
CSharpCompilationOptions? cSharpCompilationOptions
)
{
metadataReferences ??= DefaultMetadataReferences;
cSharpCompilationOptions ??= DefaultCSharpCompilationOptions;

Expand Down Expand Up @@ -97,11 +110,14 @@ Action<string> assertAction

internal static GeneratedSource? InternalGetSource(this GeneratorDriverRunResult result, string filePathEndsWith)
{
var sources = InternalGetSources(result);

var matchingSources = sources.Where(x => x.FilePath.EndsWith(filePathEndsWith, StringComparison.InvariantCultureIgnoreCase)).ToList();

return matchingSources.Count == 0 ? null : matchingSources[0];
foreach (var generatedTree in result.GeneratedTrees)
{
var source = GetGeneratedSource(generatedTree);
if (source.FilePath.EndsWith(filePathEndsWith, StringComparison.InvariantCultureIgnoreCase))
return source;
}

return null;
}

internal static ImmutableList<GeneratedSource> InternalGetSources(this GeneratorDriverRunResult result)
Expand Down
40 changes: 24 additions & 16 deletions src/SourceGeneratorTestHelpers/IncrementalGenerator.cs
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Expand Up @@ -17,18 +17,20 @@ public static class IncrementalGenerator
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The results of the <see cref="IIncrementalGenerator"/> execution.</returns>
public static GeneratorDriverRunResult Run<T>(
/// <returns>The generator instance used for the run and the result of the <see cref="IIncrementalGenerator"/> execution.</returns>
public static (T Generator, GeneratorDriverRunResult Result) Run<T>(
string source,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
CSharpCompilationOptions? cSharpCompilationOptions = null
)
where T : IIncrementalGenerator, new()
{
var generator = new T().AsSourceGenerator();
var generator = new T();
var sourceGenerator = generator.AsSourceGenerator();
var result = Helpers.InternalRunGenerator(sourceGenerator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;

return Helpers.InternalRunGenerator(generator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;
return (generator, result);
}

/// <summary>Gather compilation diagnostics and executes a specified <see cref="IIncrementalGenerator"/> against the provided sources within a testing environment.</summary>
Expand All @@ -40,18 +42,20 @@ public static GeneratorDriverRunResult Run<T>(
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The compilation diagnostics and the result of the <see cref="IIncrementalGenerator"/> execution.</returns>
public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult Result) RunWithDiagnostics<T>(
/// <returns>The generator instance used for the run, the result of the <see cref="IIncrementalGenerator"/> execution, and the compilation diagnostics.</returns>
public static (T Generator, GeneratorDriverRunResult Result, ImmutableArray<Diagnostic> Diagnostics) RunWithDiagnostics<T>(
string source,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
CSharpCompilationOptions? cSharpCompilationOptions = null
)
where T : IIncrementalGenerator, new()
{
var generator = new T().AsSourceGenerator();
var generator = new T();
var sourceGenerator = generator.AsSourceGenerator();
var result = Helpers.InternalRunGenerator(sourceGenerator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);

return Helpers.InternalRunGenerator(generator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);
return (generator, result.Result, result.CompilationDiagnostics);
}

/// <summary>Executes a specified <see cref="IIncrementalGenerator"/> against the provided sources within a testing environment.</summary>
Expand All @@ -63,18 +67,20 @@ public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The result of the <see cref="IIncrementalGenerator"/> execution.</returns>
public static GeneratorDriverRunResult Run<T>(
/// <returns>The generator instance used for the run and the result of the <see cref="IIncrementalGenerator"/> execution.</returns>
public static (T Generator, GeneratorDriverRunResult Result) Run<T>(
IEnumerable<string> sources,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
CSharpCompilationOptions? cSharpCompilationOptions = null
)
where T : IIncrementalGenerator, new()
{
var generator = new T().AsSourceGenerator();
var generator = new T();
var sourceGenerator = generator.AsSourceGenerator();
var result = Helpers.InternalRunGenerator(sourceGenerator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;

return Helpers.InternalRunGenerator(generator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;
return (generator, result);
}

/// <summary>Gather compilation diagnostics and executes a specified <see cref="IIncrementalGenerator"/> against the provided sources within a testing environment.</summary>
Expand All @@ -86,17 +92,19 @@ public static GeneratorDriverRunResult Run<T>(
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The compilation diagnostics and the result of the <see cref="IIncrementalGenerator"/> execution.</returns>
public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult Result) RunWithDiagnostics<T>(
/// <returns>The generator instance used for the run, the result of the <see cref="IIncrementalGenerator"/> execution, and the compilation diagnostics.</returns>
public static (T Generator, GeneratorDriverRunResult Result, ImmutableArray<Diagnostic> Diagnostics) RunWithDiagnostics<T>(
IEnumerable<string> sources,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
CSharpCompilationOptions? cSharpCompilationOptions = null
)
where T : IIncrementalGenerator, new()
{
var generator = new T().AsSourceGenerator();
var generator = new T();
var sourceGenerator = generator.AsSourceGenerator();
var result = Helpers.InternalRunGenerator(sourceGenerator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);

return Helpers.InternalRunGenerator(generator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);
return (generator, result.Result, result.CompilationDiagnostics);
}
}
34 changes: 19 additions & 15 deletions src/SourceGeneratorTestHelpers/SourceGenerator.cs
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@@ -1,4 +1,4 @@
using System.Collections.Immutable;
using System.Collections.Immutable;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using SourceGeneratorTestHelpers.Common;
Expand All @@ -17,8 +17,8 @@ public static class SourceGenerator
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The results of the <see cref="ISourceGenerator"/> execution.</returns>
public static GeneratorDriverRunResult Run<T>(
/// <returns>The generator instance used for the run and the result of the <see cref="ISourceGenerator"/> execution.</returns>
public static (T Generator, GeneratorDriverRunResult Result) Run<T>(
string source,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
Expand All @@ -27,8 +27,9 @@ public static GeneratorDriverRunResult Run<T>(
where T : ISourceGenerator, new()
{
var generator = new T();
var result = Helpers.InternalRunGenerator(generator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;

return Helpers.InternalRunGenerator(generator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;
return (generator, result);
}

/// <summary>Gather compilation diagnostics and executes a specified <see cref="ISourceGenerator"/> against the provided source within a testing environment.</summary>
Expand All @@ -40,8 +41,8 @@ public static GeneratorDriverRunResult Run<T>(
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The compilation diagnostics and the result of the <see cref="ISourceGenerator"/> execution.</returns>
public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult Result) RunWithDiagnostics<T>(
/// <returns>The generator instance used for the run, the result of the <see cref="ISourceGenerator"/> execution, and the compilation diagnostics.</returns>
public static (T Generator, GeneratorDriverRunResult Result, ImmutableArray<Diagnostic> Diagnostics) RunWithDiagnostics<T>(
string source,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
Expand All @@ -50,11 +51,12 @@ public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult
where T : ISourceGenerator, new()
{
var generator = new T();
var result = Helpers.InternalRunGenerator(generator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);

return Helpers.InternalRunGenerator(generator, source, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);
return (generator, result.Result, result.CompilationDiagnostics);
}

/// <summary>Executes a specified <see cref="ISourceGenerator"/> against the provided source within a testing environment.</summary>
/// <summary>Executes a specified <see cref="ISourceGenerator"/> against the provided sources within a testing environment.</summary>
/// <typeparam name="T">The type of <see cref="ISourceGenerator"/> to execute.</typeparam>
/// <param name="sources">The sources to be analyzed and processed by the <see cref="ISourceGenerator"/>.</param>
/// <param name="cSharpParseOptions">The C# source parsing options to compile with. By default, LangVersion will be set to latest.</param>
Expand All @@ -63,8 +65,8 @@ public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The result of the <see cref="ISourceGenerator"/> execution.</returns>
public static GeneratorDriverRunResult Run<T>(
/// <returns>The generator instance used for the run and the result of the <see cref="ISourceGenerator"/> execution.</returns>
public static (T Generator, GeneratorDriverRunResult Result) Run<T>(
IEnumerable<string> sources,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
Expand All @@ -73,11 +75,12 @@ public static GeneratorDriverRunResult Run<T>(
where T : ISourceGenerator, new()
{
var generator = new T();
var result = Helpers.InternalRunGenerator(generator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;

return Helpers.InternalRunGenerator(generator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions).Result;
return (generator, result);
}

/// <summary>Gather compilation diagnostics and executes a specified <see cref="ISourceGenerator"/> against the provided source within a testing environment.</summary>
/// <summary>Gather compilation diagnostics and executes a specified <see cref="ISourceGenerator"/> against the provided sources within a testing environment.</summary>
/// <typeparam name="T">The type of <see cref="ISourceGenerator"/> to execute.</typeparam>
/// <param name="sources">The sources to be analyzed and processed by the <see cref="ISourceGenerator"/>.</param>
/// <param name="cSharpParseOptions">The C# source parsing options to compile with. By default, LangVersion will be set to latest.</param>
Expand All @@ -86,8 +89,8 @@ public static GeneratorDriverRunResult Run<T>(
/// The C# compilation options to compile with. By default, Output will be set to library, and Nullable will be set to
/// enable.
/// </param>
/// <returns>The compilation diagnostics and the result of the <see cref="ISourceGenerator"/> execution.</returns>
public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult Result) RunWithDiagnostics<T>(
/// <returns>The generator instance used for the run, the result of the <see cref="ISourceGenerator"/> execution, and the compilation diagnostics.</returns>
public static (T Generator, GeneratorDriverRunResult Result, ImmutableArray<Diagnostic> Diagnostics) RunWithDiagnostics<T>(
IEnumerable<string> sources,
CSharpParseOptions? cSharpParseOptions = null,
IEnumerable<MetadataReference>? metadataReferences = null,
Expand All @@ -96,7 +99,8 @@ public static (ImmutableArray<Diagnostic> Diagnostics, GeneratorDriverRunResult
where T : ISourceGenerator, new()
{
var generator = new T();
var result = Helpers.InternalRunGenerator(generator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);

return Helpers.InternalRunGenerator(generator, sources, cSharpParseOptions, metadataReferences, cSharpCompilationOptions);
return (generator, result.Result, result.CompilationDiagnostics);
}
}
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