UnityTestIA - VSCode Extension for Unit Test Generation

Note

This project is part of a special assistance program at Tecnológico de Costa Rica (TEC), PROTEC area. Its purpose is to analyze the automation and efficiency of different LLMs for generating unit tests in Unity.

Overview

UnityTestIA is a Visual Studio Code extension designed to evaluate and compare several Large Language Models (LLMs) for the automatic creation of unit tests in Unity projects. The tool helps to determine which LLM provides the best results in terms of coverage and code quality.

Tip

With UnityTestIA you only need to specify the class name and method name you want to test. The extension automatically generates the necessary NUnit tests to achieve maximum decision coverage.

Key Features

• Integration with multiple LLM providers:
  • Google Gemini
  • OpenRouter (with submodels such as DeepSeek, LLaMA, etc.)
  • Easy to add more providers.
• Friendly interface inside VSCode.
• Automatic prompt building for optimal results.
• Validation of class and method before requesting tests.
• Code highlighting and copy-to-clipboard.

Deployment of the Extension

1. Clone the repository to your local machine:

   git clone https://github.com/your-user/unitytestia.git

2. Open the folder in Visual Studio Code.
3. Run:

   # install dependencies and build/watch to generate dist/ (bundle.js & bundle.css)
   npm install && npm run watch

4. Press F5 to launch the extension in a new VSCode window.

Note

Deployment to the VS Code Marketplace is planned for future releases.

Environment Variables

Create a .env file in the project root:

GEMINI_API_KEY=your_gemini_key
OPENROUTER_API_KEY=your_openrouter_key

Important

It is essential to define the keys exactly as shown in the example above so that the extension can recognize them correctly.

Extension Usage

1. Open your Unity project in Visual Studio Code from the Assets/ folder so the extension can access the source code correctly.
2. Open any C# script inside VSCode.
3. Launch the UnityTestIA command:
   • Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P).
   • Search for UnityTestIA: Generate Test.
4. Enter:
   • Class name
   • Method name
5. Choose an LLM provider and, if applicable, a submodel.
6. Click the generation button to obtain the unit test cases.

Tip

The generated tests will appear in a dedicated panel with syntax highlighting and a copy button.

Project Structure

├── prompts/
│   └── basePrompt.txt            # Prompt base usado por los LLMs
├── src/
│   ├── extension.ts              # Punto de entrada, activa la extensión en VSCode
│   ├── webview/
│   │   ├── webviewManager.ts     # Configuración y lógica del panel webview
│   │   └── collectInputs.ts      # Maneja la sincronización de inputs entre el webview y backend
│   ├── llm/
│   │   ├── gemini.ts             # Implementación de la llamada a Google Gemini
│   │   ├── openrouter.ts         # Implementación de la llamada a OpenRouter
│   │   └── index.ts              # Re-exporta de forma unificada las funciones LLM
│   ├── prompts/
│   │   └── promptBuilder.ts      # Construye el prompt final con clase, método y código
│   ├── utils/
│   │   ├── codeValidation.ts     # Verifica que la clase y el método existan en el código
│   │   └── modelLoader.ts        # Carga y valida modelos de OpenRouter desde JSON
│   └── test/
│       └── extension.test.ts     # Tests iniciales de la extensión
├── ui/
│   ├── index.html                # HTML de la interfaz webview
│   ├── scripts/
│   │   ├── main.js               # Entrada principal del frontend
│   │   ├── domUtils.js           # Utilidades genéricas de manipulación del DOM
│   │   ├── modelMenu.js          # Lógica para selección de modelos y submodelos
│   │   ├── resultRenderer.js     # Renderiza resultados devueltos por el backend
│   │   └── stepper.js            # Manejo del stepper (flujo de inputs)
│   └── styles/
│       ├── base.css              # Estilos base y globales
│       ├── main.css              # Estilos principales del layout
│       ├── components.css        # Estilos para tarjetas, botones y elementos UI
│       ├── actions.css           # Estilos específicos del contenedor de acciones
│       ├── stepper.css           # Estilos del stepper y estados
│       └── animations.css        # Animaciones y microinteracciones
├── assets/
│   └── logo.png                  # Logo mostrado en la interfaz
├── openrouter.models.json        # Configuración de submodelos de OpenRouter
└── webpack.config.js             # Configuración para generar el bundle (JS y CSS)

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Prompt Specification

The extension relies on a base prompt that defines how LLMs should generate Unity unit tests. Only an excerpt is shown here for clarity:

Important

You are an expert Software Engineer specialized in testing and quality assurance.
Your task is to generate unit tests using White Box methods.
Objective:
Generate the absolute minimum number of Unity Test Framework (NUnit 3.x)
test methods required to achieve 100% decision coverage...

(excerpt)

---

Prompt location

The complete specification is stored in:

   /prompts/basePrompt.txt

First prompt send to the LLM

The location of this .txt file is relative to your system. If you want to know the exact path, you can check it in the developer console of the extension.

/Users/yourUser/Library/Application Support/Code/User/globalStorage/undefined_publisher.unitytestia

This is the specific path in my case. It will vary depending on your system and the location of VS Code. yourUser is just an example; if you want to verify it on your machine, replace it with your actual system username.

Customization

If you want to:

• Adjust coverage strategy (e.g., black-box instead of white-box),
• Change test framework conventions,
• Or simplify the constraints,

you can directly edit the basePrompt.txt file. The extension will automatically pick up the new instructions on the next run.

Contributing

Note

Contributions are welcome! Please fork the repository and submit pull requests with clear descriptions.

License

This project is distributed under the MIT License. See the LICENSE file for more information.