wsgi_intercept installs a WSGI application in place of a real URI for testing.
installs a WSGI application in place of a real URI for testing.
Testing a WSGI application normally involves starting a server at a local host and port, then pointing your test code to that address. Instead, this library lets you intercept calls to any specific host/port combination and redirect them into a WSGI application importable by your test program. Thus, you can avoid spawning multiple processes or threads to test your Web app.
How Does It Work?
wsgi_intercept works by replacing httplib.HTTPConnection with a subclass, wsgi_intercept.WSGI_HTTPConnection. This class then redirects specific server/port combinations into a WSGI application by emulating a socket. If no intercept is registered for the host and port requested, those requests are passed on to the standard handler.
The functions add_wsgi_intercept(host, port, app_create_fn, script_name='') and remove_wsgi_intercept(host,port) specify which URLs should be redirect into what applications. Note especially that app_create_fn is a function object returning a WSGI application; script_name becomes SCRIPT_NAME in the WSGI app’s environment, if set.
pip install -U wsgi_intercept
Unfortunately each of the Web testing frameworks uses its own specific mechanism for making HTTP call-outs, so individual implementations are needed. At this time there are implementations for httplib2 and requests in both Python 2 and 3, urllib2 and httplib in Python 2 and urllib.request and http.client in Python 3.
If you are using Python 2 and need support for a different HTTP client, require a version of wsgi_intercept<0.6. Earlier versions include support for mechanize, webtest, webunit and zope.testbrowser. It is quite likely that support for these versions will be relatively to add back in to the new version.
The best way to figure out how to use interception is to inspect the tests. More comprehensive documentation available upon request.
Pursuant to Ian Bicking’s “best Web testing framework” post, Titus Brown put together an in-process HTTP-to-WSGI interception mechanism for his own Web testing system, twill. Because the mechanism is pretty generic – it works at the httplib level – Titus decided to try adding it into all of the other Python Web testing frameworks.
The Python 2 version of wsgi-intercept was the result. Kumar McMillan later took over maintenance.