Testing¶

Test utilities for Roslyn analyzers, generators, and code fixes.

Installation¶

dotnet add package Deepstaging.Roslyn.Testing --prerelease

Architecture¶

RoslynTestBase
  │
  ├── SymbolsFor(source)           → SymbolTestContext
  │     ├── RequireNamedType()       (ValidSymbol<INamedTypeSymbol>)
  │     ├── Type("Foo").Methods()    (fluent queries)
  │     └── GetProperty()            (OptionalSymbol<IPropertySymbol>)
  │
  ├── AnalyzeWith<T>(source)       → AnalyzerTestContext
  │     ├── ShouldReportDiagnostic()
  │     └── ShouldHaveNoDiagnostics()
  │
  ├── GenerateWith<T>(source)      → GeneratorTestContext
  │     ├── ShouldGenerate()
  │     ├── WithFileNamed()
  │     └── VerifySnapshot()
  │
  ├── FixWith<T>(source)           → CodeFixTestContext
  ├── AnalyzeAndFixWith<TA,TF>()   → CodeFixTestContext
  │     ├── ShouldProduce()
  │     └── ShouldAddAdditionalDocument()
  │
  └── RenderTemplateFrom<T>()     → TemplateTestContext
        ├── Render()
        └── VerifySnapshot()

Quick Start¶

All tests inherit from RoslynTestBase:

public class MyTests : RoslynTestBase
{
    [Test]
    public async Task Analyzer_reports_diagnostic()
    {
        await AnalyzeWith<MyAnalyzer>(source)
            .ShouldReportDiagnostic("MY001")
            .WithSeverity(DiagnosticSeverity.Error);
    }

    [Test]
    public async Task Generator_produces_output()
    {
        await GenerateWith<MyGenerator>(source)
            .ShouldGenerate()
            .WithFileNamed("Customer.g.cs")
            .WithNoDiagnostics()
            .VerifySnapshot();
    }

    [Test]
    public async Task CodeFix_transforms_source()
    {
        await AnalyzeAndFixWith<MyAnalyzer, MyCodeFix>(source)
            .ForDiagnostic("MY001")
            .ShouldProduce(expectedSource);
    }
}

Reference Configuration¶

If tests need your own assemblies, configure once via ModuleInitializer:

[ModuleInitializer]
public static void Init() =>
    ReferenceConfiguration.AddReferencesFromTypes(typeof(MyAttribute));

API Reference¶

Type	Description
RoslynTestBase	Entry points for all test types
SymbolTestContext	Compile source and query symbols
AnalyzerTestContext	Assert on analyzer diagnostics
GeneratorTestContext	Assert on generator output with snapshots
CodeFixTestContext	Assert on code fix transformations
TemplateTestContext	Assert on template rendering
Assertions	TUnit assertion extensions for symbols, emit, and compilations
ReferenceConfiguration	Configure assembly references for compilations