Bonus: Testing the Application — Flask 0.12.2 documentation

# Bonus: Testing the Application

Now that you have finished the application and everything works as expected, it’s probably not a bad idea to add automated tests to simplify modifications in the future. The application above is used as a basic example of how to perform unit testing in the Testing Flask Applications section of the documentation. Go there to see how easy it is to test Flask applications.

## Adding tests to flaskr

Assuming you have seen the Testing Flask Applications section and have either written your own tests for `flaskr` or have followed along with the examples provided, you might be wondering about ways to organize the project.

One possible and recommended project structure is:

    flaskr/
        flaskr/
            __init__.py
            static/
            templates/
        tests/
            test_flaskr.py
        setup.py
        MANIFEST.in

For now go ahead a create the `tests/` directory as well as the `test_flaskr.py` file.

## Running the tests

At this point you can run the tests. Here `pytest` will be used.

Note

Make sure that `pytest` is installed in the same virtualenv as flaskr. Otherwise `pytest` test will not be able to import the required components to test the application:

    pip install -e .
    pip install pytest

Run and watch the tests pass, within the top-level `flaskr/` directory as:

    py.test

## Testing + setuptools

One way to handle testing is to integrate it with `setuptools`. Here that requires adding a couple of lines to the `setup.py` file and creating a new file `setup.cfg`. One benefit of running the tests this way is that you do not have to install `pytest`. Go ahead and update the `setup.py` file to contain:

    from setuptools import setup

    setup(
        name='flaskr',
        packages=['flaskr'],
        include_package_data=True,
        install_requires=[
            'flask',
        ],
        setup_requires=[
            'pytest-runner',
        ],
        tests_require=[
            'pytest',
        ],
    )

Now create `setup.cfg` in the project root (alongside `setup.py`):

    [aliases]
    test=pytest

Now you can run:

    python setup.py test

This calls on the alias created in `setup.cfg` which in turn runs `pytest` via `pytest-runner`, as the `setup.py` script has been called. (Recall the setup_requires argument in `setup.py`) Following the standard rules of test-discovery your tests will be found, run, and hopefully pass.

This is one possible way to run and manage testing. Here `pytest` is used, but there are other options such as `nose`. Integrating testing with `setuptools` is convenient because it is not necessary to actually download `pytest` or any other testing framework one might use.