pytest-tornado

A py.test plugin providing fixtures and markers to simplify testing of asynchronous tornado applications.

Installation

pip install pytest-tornado

Example

import pytest
import tornado.web

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")

application = tornado.web.Application([
    (r"/", MainHandler),
])

@pytest.fixture
def app():
    return application

@pytest.mark.gen_test
def test_hello_world(http_client, base_url):
    response = yield http_client.fetch(base_url)
    assert response.code == 200

Running tests

py.test

Fixtures

io_loop: creates an instance of the tornado.ioloop.IOLoop for each test case
http_port: get a port used by the test server
base_url: get an absolute base url for the test server, for example, http://localhost:59828
http_server: start a tornado HTTP server, you must create an app fixture, which returns the tornado.web.Application to be tested
http_client: get an asynchronous HTTP client

Show fixtures provided by the plugin:

py.test --fixtures

Markers

A gen_test marker lets you write a coroutine-style tests used with the tornado.gen module:

@pytest.mark.gen_test
def test_tornado(http_client):
    response = yield http_client.fetch('http://www.tornadoweb.org/')
    assert response.code == 200

Marked tests will time out after 5 seconds. The timeout can be modified by setting an ASYNC_TEST_TIMEOUT environment variable, --async-test-timeout command line argument or a marker argument.

@pytest.mark.gen_test(timeout=5)
def test_tornado(http_client):
    yield http_client.fetch('http://www.tornadoweb.org/')

Show markers provided by the plugin: