wsgisupp: implement support code for the testing of WSGI handlers/servers

Author: albu-diku

local-requirements.txt

@@ -7,3 +7,4 @@ autopep8;python_version >= "3"
 # NOTE: paramiko-3.0.0 dropped python2 and python3.6 support
 paramiko;python_version >= "3.7"
 paramiko<3;python_version < "3.7"
+werkzeug

tests/support/wsgisupp.py

@@ -0,0 +1,161 @@
+# -*- coding: utf-8 -*-
+#
+# --- BEGIN_HEADER ---
+#
+# htmlsupp - test support library for WSGI
+# Copyright (C) 2003-2024  The MiG Project by the Science HPC Center at UCPH
+#
+# This file is part of MiG.
+#
+# MiG is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# MiG is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# -- END_HEADER ---
+#
+
+from collections import namedtuple
+import codecs
+from io import BytesIO
+from werkzeug.datastructures import MultiDict
+
+from tests.support._env import PY2
+
+if PY2:
+    from urllib import urlencode
+    from urlparse import urlparse
+else:
+    from urllib.parse import urlencode, urlparse
+
+"""Test support library for WSGI."""
+
+
+_PreparedWsgi = namedtuple('_PreparedWsgi', ['environ', 'start_response'])
+
+
+class FakeWsgiStartResponse:
+    """Glue object that conforms to the same interface as the start_response()
+       in the WSGI specs but records the calls to it such that they can be
+       inspected and, for our purposes, asserted against."""
+
+    def __init__(self):
+        self.calls = []
+
+    def __call__(self, status, headers, exc=None):
+        self.calls.append((status, headers, exc))
+
+
+def create_wsgi_environ(configuration, wsgi_url, method='GET', query=None, headers=None, form=None):
+    parsed_url = urlparse(wsgi_url)
+
+    if query:
+        method = 'GET'
+
+        request_query = urlencode(query)
+        wsgi_input = ()
+    elif form:
+        method = 'POST'
+        request_query = ''
+
+        body = urlencode(MultiDict(form)).encode('ascii')
+
+        headers = headers or {}
+        if not 'Content-Type' in headers:
+            headers['Content-Type'] = 'application/x-www-form-urlencoded'
+
+        headers['Content-Length'] = str(len(body))
+        wsgi_input = BytesIO(body)
+    else:
+        request_query = parsed_url.query
+        wsgi_input = ()
+
+    class _errors:
+        def close():
+            pass
+
+    environ = {}
+    environ['wsgi.errors'] = _errors()
+    environ['wsgi.input'] = wsgi_input
+    environ['wsgi.url_scheme'] = parsed_url.scheme
+    environ['wsgi.version'] = (1, 0)
+    environ['MIG_CONF'] = configuration.config_file
+    environ['HTTP_HOST'] = parsed_url.netloc
+    environ['PATH_INFO'] = parsed_url.path
+    environ['QUERY_STRING'] = request_query
+    environ['REQUEST_METHOD'] = method
+    environ['SCRIPT_URI'] = ''.join(('http://', environ['HTTP_HOST'], environ['PATH_INFO']))
+
+    if headers:
+        for k, v in headers.items():
+            header_key = k.replace('-', '_').upper()
+            if header_key.startswith('CONTENT'):
+                # Content-* headers must not be prefixed in WSGI
+                pass
+            else:
+                header_key = "HTTP_%s" % (header_key),
+            environ[header_key] = v
+
+    return environ
+
+
+def create_wsgi_start_response():
+    return FakeWsgiStartResponse()
+
+
+def prepare_wsgi(configuration, url, **kwargs):
+    return _PreparedWsgi(
+        create_wsgi_environ(configuration, url, **kwargs),
+        create_wsgi_start_response()
+    )
+
+
+def _trigger_and_unpack_result(wsgi_result):
+    chunks = list(wsgi_result)
+    assert len(chunks) > 0, "invocation returned no output"
+    complete_value = b''.join(chunks)
+    decoded_value = codecs.decode(complete_value, 'utf8')
+    return decoded_value
+
+
+class WsgiAssertMixin:
+    """Custom assertions for verifying server code executed under test."""
+
+    def assertWsgiResponse(self, wsgi_result, fake_wsgi, expected_status_code):
+        assert isinstance(fake_wsgi, _PreparedWsgi)
+
+        content = _trigger_and_unpack_result(wsgi_result)
+
+        def called_once(fake):
+            assert hasattr(fake, 'calls')
+            return len(fake.calls) == 1
+
+        fake_start_response = fake_wsgi.start_response
+
+        try:
+            self.assertTrue(called_once(fake_start_response))
+        except AssertionError:
+            if len(fake.calls) == 0:
+                raise AssertionError("WSGI handler did not respond")
+            else:
+                raise AssertionError("WSGI handler responded more than once")
+
+        wsgi_call = fake_start_response.calls[0]
+
+        # check for expected HTTP status code
+        wsgi_status = wsgi_call[0]
+        actual_status_code = int(wsgi_status[0:3])
+        self.assertEqual(actual_status_code, expected_status_code)
+
+        headers = dict(wsgi_call[1])
+
+        return content, headers