test_exceptions_handler.py

from sanic import Sanic
from sanic.response import text
from sanic.exceptions import InvalidUsage, ServerError, NotFound
from sanic.handlers import ErrorHandler
from bs4 import BeautifulSoup

exception_handler_app = Sanic('test_exception_handler')


@exception_handler_app.route('/1')
def handler_1(request):
    raise InvalidUsage("OK")


@exception_handler_app.route('/2')
def handler_2(request):
    raise ServerError("OK")


@exception_handler_app.route('/3')
def handler_3(request):
    raise NotFound("OK")


@exception_handler_app.route('/4')
def handler_4(request):
    foo = bar    # noqa -- F821 undefined name 'bar' is done to throw exception
    return text(foo)


@exception_handler_app.route('/5')
def handler_5(request):
    class CustomServerError(ServerError):
        pass
    raise CustomServerError('Custom server error')


@exception_handler_app.route('/6/<arg:int>')
def handler_6(request, arg):
    try:
        foo = 1 / arg
    except Exception as e:
        raise e from ValueError("{}".format(arg))
    return text(foo)


@exception_handler_app.exception(NotFound, ServerError)
def handler_exception(request, exception):
    return text("OK")


def test_invalid_usage_exception_handler():
    request, response = exception_handler_app.test_client.get('/1')
    assert response.status == 400


def test_server_error_exception_handler():
    request, response = exception_handler_app.test_client.get('/2')
    assert response.status == 200
    assert response.text == 'OK'


def test_not_found_exception_handler():
    request, response = exception_handler_app.test_client.get('/3')
    assert response.status == 200


def test_text_exception__handler():
    request, response = exception_handler_app.test_client.get('/random')
    assert response.status == 200
    assert response.text == 'OK'


def test_html_traceback_output_in_debug_mode():
    request, response = exception_handler_app.test_client.get(
        '/4', debug=True)
    assert response.status == 500
    soup = BeautifulSoup(response.body, 'html.parser')
    html = str(soup)

    assert 'response = handler(request, *args, **kwargs)' in html
    assert 'handler_4' in html
    assert 'foo = bar' in html

    summary_text = " ".join(soup.select('.summary')[0].text.split())
    assert (
        "NameError: name 'bar' "
        "is not defined while handling path /4") == summary_text


def test_inherited_exception_handler():
    request, response = exception_handler_app.test_client.get('/5')
    assert response.status == 200


def test_chained_exception_handler():
    request, response = exception_handler_app.test_client.get(
        '/6/0', debug=True)
    assert response.status == 500

    soup = BeautifulSoup(response.body, 'html.parser')
    html = str(soup)

    assert 'response = handler(request, *args, **kwargs)' in html
    assert 'handler_6' in html
    assert 'foo = 1 / arg' in html
    assert 'ValueError' in html
    assert 'The above exception was the direct cause' in html

    summary_text = " ".join(soup.select('.summary')[0].text.split())
    assert (
        "ZeroDivisionError: division by zero "
        "while handling path /6/0") == summary_text


def test_exception_handler_lookup():
    class CustomError(Exception):
        pass

    class CustomServerError(ServerError):
        pass

    def custom_error_handler():
        pass

    def server_error_handler():
        pass

    def import_error_handler():
        pass

    try:
        ModuleNotFoundError
    except:
        class ModuleNotFoundError(ImportError):
            pass

    handler = ErrorHandler()
    handler.add(ImportError, import_error_handler)
    handler.add(CustomError, custom_error_handler)
    handler.add(ServerError, server_error_handler)

    assert handler.lookup(ImportError()) == import_error_handler
    assert handler.lookup(ModuleNotFoundError()) == import_error_handler
    assert handler.lookup(CustomError()) == custom_error_handler
    assert handler.lookup(ServerError('Error')) == server_error_handler
    assert handler.lookup(CustomServerError('Error')) == server_error_handler

    # once again to ensure there is no caching bug
    assert handler.lookup(ImportError()) == import_error_handler
    assert handler.lookup(ModuleNotFoundError()) == import_error_handler
    assert handler.lookup(CustomError()) == custom_error_handler
    assert handler.lookup(ServerError('Error')) == server_error_handler
    assert handler.lookup(CustomServerError('Error')) == server_error_handler