def test_template_filter():
    bp = flask.Blueprint('bp', __name__)
    @bp.app_template_filter()
    def my_reverse(s):
        return s[::-1]
    app = flask.Flask(__name__)
    app.register_blueprint(bp, url_prefix='/py')
    assert app.jinja_env.filters.keys() in 'my_reverse'
    assert app.jinja_env.filters['my_reverse'] == my_reverse
    assert app.jinja_env.filters['my_reverse']('abcd') == 'dcba'
dataset/ETHPy150Open pallets/flask/tests/test_blueprints.py/test_template_filter/swapped operands of `in`