TestHarness.Analyzers 0.1.0-1

This package has been deprecated as it is legacy and is no longer maintained.

This is a prerelease version of TestHarness.Analyzers.

This package has a SemVer 2.0.0 package version: 0.1.0-1+9.

dotnet add package TestHarness.Analyzers --version 0.1.0-1

NuGet\Install-Package TestHarness.Analyzers -Version 0.1.0-1

This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.

<PackageReference Include="TestHarness.Analyzers" Version="0.1.0-1">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>

For projects that support PackageReference, copy this XML node into the project file to reference the package.

<PackageVersion Include="TestHarness.Analyzers" Version="0.1.0-1" />
                    

                            Directory.Packages.props

<PackageReference Include="TestHarness.Analyzers">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>
                    

                            Project file

For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package.

paket add TestHarness.Analyzers --version 0.1.0-1

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

#r "nuget: TestHarness.Analyzers, 0.1.0-1"

#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.

#:package TestHarness.Analyzers@0.1.0-1

#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package.

#addin nuget:?package=TestHarness.Analyzers&version=0.1.0-1&prerelease
                    

                            Install as a Cake Addin

#tool nuget:?package=TestHarness.Analyzers&version=0.1.0-1&prerelease
                    

                            Install as a Cake Tool

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

TestHarness.Analyzers

A Roslyn analyzer library that detects code patterns blocking "seams" in legacy code, based on Michael Feathers' Working Effectively with Legacy Code.

What are Seams?

A seam is a place where you can alter behavior in your program without editing in that place. Seams are essential for testing because they allow you to substitute dependencies, mock behaviors, and isolate code under test.

This analyzer identifies 18 anti-patterns (SEAM001-SEAM018) across 5 categories that hinder testability by blocking seams.

Installation

dotnet add package TestHarness.Analyzers

Or via Package Manager:

Install-Package TestHarness.Analyzers

Diagnostic Rules

Direct Dependencies

Rule	Description
SEAM001	Direct instantiation of concrete types
SEAM002	Concrete type parameters without abstraction
SEAM003	Factory method returns concrete type

Static Dependencies

Rule	Description
SEAM004	Static method calls
SEAM005	Static property access
SEAM006	Extension method dependency
SEAM007	Static event subscription
SEAM008	Ambient context usage

Inheritance Blockers

Rule	Description
SEAM009	Sealed class prevents inheritance
SEAM010	Non-virtual method prevents override
SEAM011	Private method contains logic

Global State

Rule	Description
SEAM012	Singleton pattern usage
SEAM013	Static mutable field
SEAM014	Service locator pattern

Infrastructure Dependencies

Rule	Description
SEAM015	Direct file system access
SEAM016	Direct HTTP client usage
SEAM017	Direct database access
SEAM018	Direct process invocation

Configuration

Suppress diagnostics or exclude specific types via .editorconfig:

# Disable a rule entirely
dotnet_diagnostic.SEAM001.severity = none

# Exclude specific types from SEAM001
dotnet_code_quality.SEAM001.excluded_types = T:MyNamespace.AllowedFactory

# Exclude specific methods from SEAM004
dotnet_code_quality.SEAM004.excluded_methods = M:System.Console.WriteLine

Example

public class OrderService
{
    // SEAM001: Direct instantiation creates hard dependency
    private readonly EmailService _emailService = new EmailService();

    // Better: Inject the dependency
    private readonly IEmailService _emailService;

    public OrderService(IEmailService emailService)
    {
        _emailService = emailService;
    }
}

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

Acknowledgments

This project is inspired by Michael Feathers' book Working Effectively with Legacy Code. The concept of "seams" as places where you can alter program behavior without editing in that place comes directly from his work. Thank you to Michael Feathers for providing such valuable insights into making legacy code testable.

License

This project is licensed under the MIT License - see the LICENSE file for details.

There are no supported framework assets in this package.

Learn more about Target Frameworks and .NET Standard.

.NETStandard 2.0
- No dependencies.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version	Downloads	Last Updated
0.1.0-1	71	1/16/2026