🧪 AI Test Case Generator

A modern Python framework that auto-generates pytest test cases and optionally an Excel test case sheet from plain English requirements using LLMs. Supports both OpenAI API and Ollama local models, configurable via config.ini.

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✨ Features

• 📄 Natural language → Tests: Write your acceptance criteria in criteria/criterion.txt, and let the framework generate pytest code.
• 📊 Excel export: Optionally generate a structured Excel file (.xlsx) with test case rows (Test Name, Description, Steps, Expected, etc.).
• 🔄 Flexible LLM backend: Choose between OpenAI (cloud) or Ollama (local) from config.ini.
• ⚙️ Config-driven: All keys, models, and provider settings live in config.ini (no env vars needed).
• 🛡️ Safe defaults: Deterministic generation (temperature=0), code-only outputs, and syntax validation.
• 🔁 Fallbacks: Optionally switch to a backup provider if the primary one fails.

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📂 Project Structure

testgen-openai/
├─ criteria/              # Requirement specs in plain text
│  └─ criterion.txt        # Write your acceptance criteria here
├─ testgen/               # Core framework
│  ├─ __init__.py
│  ├─ reader.py
│  ├─ prompt.py
│  ├─ config_loader.py
│  ├─ openai_client.py
│  ├─ ollama_client.py
│  ├─ llm_router.py       # Provider selection logic
│  ├─ excel_writer.py     # Excel export module
│  └─ generator.py
├─ tests/
│  ├─ test_generated.py   # Auto-generated tests (do not edit)
│  └─ test_cases.xlsx     # Optional Excel test cases
├─ config.ini             # All settings (provider, API keys, models, export flag)
├─ requirements.txt
└─ run_generate.py        # CLI entrypoint

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🚀 Quickstart

1. Clone & Setup

git clone <your-repo-url> aitestgen
cd aitestgen
python -m venv .venv
source .venv/bin/activate   # mac/linux
.\.venv\Scripts\activate    # windows
pip install -r requirements.txt

2. Configure

Edit config.ini:

[llm]
provider = openai         # or ollama
fallback_enabled = true
fallback_provider = ollama

[openai]
api_key = sk-...
model = gpt-3.5-turbo

[ollama]
host = http://localhost:11434
model = gemma3:4b

[export]
excel = true              # enable Excel export
excel_path = tests/test_cases.xlsx

3. Add Requirements

Put your acceptance criteria in criteria/criterion.txt, for example:

1. Login: Valid credentials should sign in the user and redirect to the dashboard within 3 seconds.
2. Login: Incorrect password should display the message "Invalid email or password." without revealing which field is wrong.
3. Signup: Password must meet strength rules (≥8 chars, uppercase, lowercase, number, special character).
...

A longer sample file is already included with 15 UI acceptance criteria.

4. Generate Tests

python run_generate.py --criterion criteria/criterion.txt

Generated artifacts:

• ✅ tests/test_generated.py (pytest tests)
• 📊 tests/test_cases.xlsx (Excel test sheet, if enabled)

5. Run Tests

pytest -q

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⚡ Switching Providers

• To use OpenAI: set [llm] provider=openai and fill [openai] api_key.
• To use Ollama: set [llm] provider=ollama and ensure Ollama server is running (ollama serve).
• You can enable automatic fallback in config.ini.

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🛠️ Developer Notes

• 🧩 Prompt design lives in testgen/prompt.py — tweak it to change generation style.
• ✅ Generated code is syntax-checked before writing.
• 🧪 Supports pytest.raises for exceptions.
• 📊 Excel export uses openpyxl — lightweight and configurable.
• 🔒 API keys are never hard-coded — only read from config.ini.

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📜 License

MIT — free to use, modify, and share.

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🙌 Acknowledgements

• OpenAI for API access.
• Ollama for local LLMs.
• pytest for a clean testing experience.
• openpyxl for Excel generation.

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🚧 Tip: Review generated tests before committing them to production. LLMs may make assumptions about imports or edge cases.