Test Utilities — Werkzeug documentation
Test Utilities
Quite often you want to unittest your application or just check the output from an interactive python session. In theory that is pretty simple because you can fake a WSGI environment and call the application with a dummy start_response and iterate over the application iterator but there are argumentably better ways to interact with an application.
Diving In
Werkzeug provides a Client object which you can pass a WSGI application (and optionally a response wrapper) which you can use to send virtual requests to the application.
A response wrapper is a callable that takes three arguments: the application iterator, the status and finally a list of headers. The default response wrapper returns a tuple. Because response objects have the same signature, you can use them as response wrapper, ideally by subclassing them and hooking in test functionality.
>>> from werkzeug.test import Client
>>> from werkzeug.testapp import test_app
>>> from werkzeug.wrappers import BaseResponse
>>> c = Client(test_app, BaseResponse)
>>> resp = c.get('/')
>>> resp.status_code
200
>>> resp.headers
Headers([('Content-Type', 'text/html; charset=utf-8'), ('Content-Length', '6658')])
>>> resp.data.splitlines()[0]
b'<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"'Or without a wrapper defined:
>>> c = Client(test_app)
>>> app_iter, status, headers = c.get('/')
>>> status
'200 OK'
>>> headers
Headers([('Content-Type', 'text/html; charset=utf-8'), ('Content-Length', '6658')])
>>> b''.join(app_iter).splitlines()[0]
b'<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"'Environment Building
New in version 0.5.
The easiest way to interactively test applications is using the EnvironBuilder. It can create both standard WSGI environments and request objects.
The following example creates a WSGI environment with one uploaded file and a form field:
>>> from werkzeug.test import EnvironBuilder
>>> from io import BytesIO
>>> builder = EnvironBuilder(method='POST', data={'foo': 'this is some text',
... 'file': (BytesIO('my file contents'.encode("utf8")), 'test.txt')})
>>> env = builder.get_environ()The resulting environment is a regular WSGI environment that can be used for further processing:
>>> from werkzeug.wrappers import Request
>>> req = Request(env)
>>> req.form['foo']
'this is some text'
>>> req.files['file']
<FileStorage: u'test.txt' ('text/plain')>
>>> req.files['file'].read()
b'my file contents'The EnvironBuilder figures out the content type automatically if you pass a dict to the constructor as data. If you provide a string or an input stream you have to do that yourself.
By default it will try to use application/x-www-form-urlencoded and only use multipart/form-data if files are uploaded:
>>> builder = EnvironBuilder(method='POST', data={'foo': 'bar'})
>>> builder.content_type
'application/x-www-form-urlencoded'
>>> builder.files['foo'] = BytesIO('contents'.encode("utf8"))
>>> builder.content_type
'multipart/form-data'If a string is provided as data (or an input stream) you have to specify the content type yourself:
>>> builder = EnvironBuilder(method='POST', data='{"json": "this is"}')
>>> builder.content_type
>>> builder.content_type = 'application/json'Testing API
