How to use the webtest.lint.middleware function in WebTest

"""
        Executes the given request (``req``), with the expected
        ``status``.  Generally ``.get()`` and ``.post()`` are used
        instead.
        """
        __tracebackhide__ = True
        errors = StringIO()
        req.environ['wsgi.errors'] = errors
        if self.cookies:
            c = BaseCookie()
            for name, value in self.cookies.items():
                c[name] = value
            req.environ['HTTP_COOKIE'] = str(c).split(': ', 1)[1]
        req.environ['paste.testing'] = True
        req.environ['paste.testing_variables'] = {}
        app = lint.middleware(self.app)
        old_stdout = sys.stdout
        out = CaptureStdout(old_stdout)
        try:
            sys.stdout = out
            start_time = time.time()
            ## FIXME: should it be an option to not catch exc_info?
            res = req.get_response(app, catch_exc_info=True)
            end_time = time.time()
        finally:
            sys.stdout = old_stdout
            sys.stderr.write(out.getvalue())
        res.app = app
        res.test_app = self
        # We do this to make sure the app_iter is exausted:
        res.body
        res.errors = errors.getvalue()

Note you can pass any keyword arguments to
        ``TestRequest.blank()``, which will be set on the request.
        These can be arguments like ``content_type``, ``accept``, etc.
        """
        __tracebackhide__ = True
        errors = StringIO()
        req.environ['wsgi.errors'] = errors
        if self.cookies:
            cookie_header = ''.join([
                '%s="%s"; ' % (name, cookie_quote(value))
                for name, value in self.cookies.items()])
            req.environ['HTTP_COOKIE'] = cookie_header
        req.environ['paste.testing'] = True
        req.environ['paste.testing_variables'] = {}
        app = lint.middleware(self.app)
        old_stdout = sys.stdout
        out = CaptureStdout(old_stdout)
        try:
            sys.stdout = out
            start_time = time.time()
            ## FIXME: should it be an option to not catch exc_info?
            res = req.get_response(app, catch_exc_info=True)
            end_time = time.time()
        finally:
            sys.stdout = old_stdout
        res.app = app
        res.test_app = self
        # We do this to make sure the app_iter is exausted:
        res.body
        res.errors = errors.getvalue()
        total_time = end_time - start_time

def test_lint_iterator_returned(self):
        linter = middleware(lambda x, y: None)  # None is not an iterator
        msg = "The application must return an iterator, if only an empty list"
        with self.assertRaisesRegexp(AssertionError, msg):
            linter({'wsgi.input': 'foo', 'wsgi.errors': 'foo'}, 'foo')

errors = StringIO()
        req.environ['wsgi.errors'] = errors
        script_name = req.environ.get('SCRIPT_NAME', '')
        if script_name and req.path_info.startswith(script_name):
            req.path_info = req.path_info[len(script_name):]

        # set framework hooks
        req.environ['paste.testing'] = True
        req.environ['paste.testing_variables'] = {}

        # set request cookies
        self.cookiejar.add_cookie_header(utils._RequestCookieAdapter(req))

        # verify wsgi compatibility
        app = lint.middleware(self.app) if self.lint else self.app

        # FIXME: should it be an option to not catch exc_info?
        res = req.get_response(app, catch_exc_info=True)

        # be sure to decode the content
        res.decode_content()

        # set a few handy attributes
        res._use_unicode = self.use_unicode
        res.request = req
        res.app = app
        res.test_app = self

        # We do this to make sure the app_iter is exhausted:
        try:
            res.body

def do_request(app, expect_status=500):
    app = lint.middleware(app)
    app = ErrorMiddleware(app, {}, debug=True)
    app = clear_middleware(app)
    testapp = TestApp(app)
    res = testapp.get('', status=expect_status,
                      expect_errors=True)
    return res