Testing code that requires a Flask app or request context

Solution 1:

If you want to make a request to your application, use the test_client.

c = app.test_client()
response = c.get('/test/url')
# test response

If you want to test code which uses an application context (current_app, g, url_for), push an app_context.

with app.app_context():
    # test your app context code

If you want test code which uses a request context (request, session), push a test_request_context.

with current_app.test_request_context():
    # test your request context code

Both app and request contexts can also be pushed manually, which is useful when using the interpreter.

>>> ctx = app.app_context()
>>> ctx.push()

Flask-Script or the new Flask cli will automatically push an app context when running the shell command.

Flask-Testing is a useful library that contains helpers for testing Flask apps.