Unit testing Flask Babel translations

Question

I'd like to do some unit tests to check my flask app translations. I have tried this piece of code:

def test_pt_br(self):
    with app.test_request_context():
        app.config['BABEL_DEFAULT_LOCALE'] = 'pt_BR'
        rv = app.test_client().get('/')
        assert 'Execute, melhore' in str(rv.data)

However, it does not work/pass although the app runs fine. What am I doing wrong?

Answer 1

The code you have shown seems to work for me. Please see here complete example based on your description: https://github.com/loomchild/flask_babel_test. When I run ./flask_babel_test_test.py both tests pass.

Could you provide complete source code that allows to reproduce the problem?

Currently I can imagine the following solutions (both of them are present in commented-out sections in the example code linked above):

1. There is some caching involved - try to execute flask.ext.babel.refresh() after updating default locale during the test and see if it helps.

2. If you retrieve browser language automatically from Accept-Language HTTP header using localeselector, for example like this:

   @babel.localeselector
   def get_locale():
       translations = [str(translation) for translation in babel.list_translations()]
       return request.accept_languages.best_match(translations)
   

   Then instead of modifying app config during the test, specify a header:

   rv = app.test_client().get('/', headers=[("Accept-Language", "pt_BR")])
   

3. Flask-Babel cannot find the translations directory during testing. It looks for them in app["BABEL_TRANSLATION_DIRECTORIES"] config setting (translations by default). The path can be absolute or relative to app.root_path (print this variable in your test if you are not sure where it points to). You can specify multiple paths separated by ;.