Alchemist

Generate a dedicated UnitTests project with placeholder unit tests for a C# solution with one command.

Alchemist is for .NET developers who want a fast and consistent starting point for test coverage without handwriting each test class, method and attribute from scratch.

Install

Install as a global .NET tool.

dotnet tool install --global KuBuCo.Alchemist

The published tool now targets .NET 8 to reduce install friction on real user machines. The solution you run it against can still target newer SDKs, but that solution must have the SDKs it needs on the machine where generation runs.

Install into a local tool manifest.

dotnet new tool-manifest
dotnet tool install KuBuCo.Alchemist

Then run it with

alchemist --help

Use alchemist-demo to familiarise yourself with Alchemist.

Quick Start

Run Alchemist against a C# solution.

alchemist --solution ./mysolution.sln

Pick a different test framework when needed.

alchemist --solution ./mysolution.sln --framework nunit

Choose how reruns should behave.

alchemist --solution ./mysolution.sln --regeneration.mode update

Example

Source Code

namespace example;

public sealed class Calculator
{
    public int Add(int left, int right)
    {
        return left + right;
    }
}

Command:

alchemist --solution ./example.sln

Result

• Generates UnitTests/UnitTests.csproj.
• Adds the selected test framework together with shared test dependencies.
• Generates a placeholder unit test file for Calculator.

Example Output

using Xunit;

namespace UnitTests.Example;

public class CalculatorUnitTests
{
    // [UnitTestID=6A1B2C3D4E5F6789]
    [Fact(Skip = "Unit test not implemented.")]
    public void Add_UnitTestPlaceholder()
    {
        Assert.True(false, "Scaffolded Unit Test");
    }
}

Supported Scenarios

Alchemist Supports

• C# Solutions
• Source projects that share one target framework.
• xUnit, nUnit, and msTest.
• The generation of placeholder unit tests for public methods.
• Execution from the solution or from elsewhere when --solution points at the target .sln.

What it Generates

• A sibling UnitTests/UnitTests.csproj.
• Project references back to the source projects it examined.
• Framework-specific test packages together with shared dependencies, such as Microsoft.NET.Test.Sdk and Moq.
• *UnitTests.cs files in a parallel UnitTests/ tree.
• Unit test methods named <SourceMethodName>_UnitTestPlaceholder.
• UnitTestID comments to make regeneration safer.

Regeneration Behavior

• Skip: Retains existing files and adds missing members.
• Update: Replaces matching methods and appends members.
• Replace: Overwrites the target file.
• --regeneration.labels false: Disables UnitTestID comments although labels are recommended when intending to rerun.

Limitations

• Alchemist generates starting points not finished unit tests.
• The default output is scaffolded and labelled as not implemented.
• It targets public methods not each source shape in a codebase.
• It expects supported projects and one shared target framework across source projects.
• In Update mode, matched methods are replaced as full methods so manual edits inside them can be overwritten.