CodeFixTestContext¶

Test Roslyn code fix providers with before/after source assertions.

Creating¶

For Analyzer Diagnostics¶

await AnalyzeAndFixWith<MyAnalyzer, MyCodeFix>(source)
    .ForDiagnostic("MY001")
    .ShouldProduce(expectedSource);

For Compiler Diagnostics¶

await FixWith<MyCodeFix>(source)
    .ForDiagnostic("CS0246")
    .ShouldProduce(expectedSource);

Methods¶

Method	Returns	Description
`WithAnalyzer<T>()`	`CodeFixTestContext`	Specify analyzer (alternative to `AnalyzeAndFixWith`)
`WithAdditionalText(path, content)`	`CodeFixTestContext`	Add an additional text file
`ForDiagnostic(id)`	`CodeFixAssertion`	Specify which diagnostic to fix

CodeFixAssertion¶

Assertions for code fix results:

Method	Returns	Description
`ShouldProduce(expectedSource)`	`Task`	Assert the fixed source matches expected
`ShouldAddAdditionalDocument()`	`AdditionalDocumentAssertion`	Assert an additional document was created
`ShouldAddSourceDocument()`	`SourceDocumentAssertion`	Assert a source document was created
`ShouldOfferFix(title?)`	`Task`	Assert a code fix was offered (optionally with specific title)
`ShouldNotOfferFix()`	`Task`	Assert no code fix was offered

Document Assertions¶

For code fixes that create additional or source documents:

AdditionalDocumentAssertion¶

await AnalyzeAndFixWith<MyAnalyzer, MyCodeFix>(source)
    .ForDiagnostic("MY001")
    .ShouldAddAdditionalDocument()
    .WithPathContaining("Templates/")
    .WithContentContaining("{{ model.name }}")
    .WithoutContentContaining("sealed");

SourceDocumentAssertion¶

await AnalyzeAndFixWith<MyAnalyzer, MyCodeFix>(source)
    .ForDiagnostic("MY001")
    .ShouldAddSourceDocument()
    .WithPathContaining("Generated/")
    .WithContentContaining("partial class");

Both assertion types support:

Method	Returns	Description
`WithPathContaining(fragment)`	self	Assert path contains substring
`WithContentContaining(text)`	self	Assert content contains text
`WithoutContentContaining(text)`	self	Assert content excludes text

Example¶

[Test]
public async Task Adds_partial_modifier()
{
    const string source = """
        [AutoNotify]
        public class Customer { }
        """;

    const string expected = """
        [AutoNotify]
        public partial class Customer { }
        """;

    await AnalyzeAndFixWith<MustBePartialAnalyzer, AddPartialCodeFix>(source)
        .ForDiagnostic("RK1002")
        .ShouldProduce(expected);
}

[Test]
public async Task Creates_template_file()
{
    await AnalyzeAndFixWith<ScaffoldAnalyzer, ScaffoldCodeFix>(source)
        .ForDiagnostic("DSRK005")
        .ShouldAddAdditionalDocument()
        .WithPathContaining("Templates/")
        .WithContentContaining("{{ model.name }}");
}