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Mock web server for testing web clients

Project description


This tool provides an in-process WSGI server on an ephemeral port.
It is intended for use in unit tests, when the system under test makes outgoing HTTP connections that cannot easily be mocked.


First, create a WSGI application that represents the fake web server you want to create.
This is simpler than it seems; for example::

def simple_app(environ, start_response):
status = '200 OK'
headers = [('Content-type', 'text/plain')]
start_response(status, headers)
return ['Hello, world!\n']

Next, activate the test server.
There are several ways to do this, but all of them produce a port number.

As a context manager::

from mockweb import mock_server
def test_web_request():
with mock_server(simple_app) as port:

As a decorator::

from mockweb import mock_server
def test_web_request(port):

Or manually started and stopped::

from mockweb import mock_server
def test_web_request():
server = mock_server(simple_app)
# ...

In the latter case, be careful to stop the server.

Mock App

The ``webmock`` package includes a simple WSGI app which behaves like the Python ``Mock``: it accepts and records any request, and allows tests to make assertions after the operation is complete.

Its usage is simple:

from mockweb import mock_server, MockApp

app = MockApp()
with mock_server(app):
# ..
app.assert_called_with('GET /foo/bar')

The assertion methods available are:

* ``assert_called_with(call)`` -- assert that the most recent request matches ``call``
* ``assert_called_once_with(call)`` -- assert that only one request was made and that it matches ``call``
* ``assert_any_call(call)`` -- assert that the any request matches ``call``
* ``assert_has_call([call, call, ..], any_order=False)`` -- assert that the given calls all occurred.
If ``any_order`` is false, the calls must be sequential.

A call can be described with a string containing the method and the path.

The mock app's behavior can be adjusted in some minor ways.
For anything more complex, build a custom WSGI app.

* ``MockApp(response='403 Forbidden')`` -- customize the HTTP response (default is "200 OK")
* ``MockApp(body='hello world\n')`` -- customize the response body (default is empty)
* ``MockApp(headers=[('X-Auth', 'abc123')])`` -- customize the response headers

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