Tests use pytests with coverage and forked plugins. Install with:

pip install -r requirements/requirements-dev.txt

Download the required test data

python prepare_data.py

Tests can be run using pytest.

• The argument --forked needs to be provided
• A coverage report can be created using the optional arguments --cov-report and --cov (see pytest documentation)
• A subset of tests can be selected by pointing to the module within tests

# run all tests, output coverage report of megatron module in terminal
pytest --forked --cov-report term --cov=megatron tests

# run tests in tests/model, output coverage report of megatron module as html
pytest --forked --cov-report html --cov=megatron tests/model

# run tests in tests/model/test_model_generation.py, don't output coverage report
pytest --forked tests/model/test_model_generation.py

Some tests can run on cpu only. These are marked with the decorator @pytest.mark.cpu. The test cases for cpu can be run with:

pytest tests -m cpu
```

If a html coverage report has been created a simple http server can be run to serve static files.

```bash
python -m http.server --directory htmlcov 8000
```


## Tips and Tricks
if You see this kind of error:
```
RuntimeError: Cannot re-initialize CUDA in forked subprocess. To use CUDA with multiprocessing, you must use the 'spawn' start method
```
It means that you used some pytorch.cuda function before the test creates the processes.