Python: How to unit test a custom HTTP request Handler?

Question

I have a custom HTTP request handler that can be simplified to something like this:

# Python 3:
from http import server

c         


        

Answer 1

Expanding on the answer from jakevdp, I managed to be able to check the output, too:

try:
    import unittest2 as unittest
except ImportError:
    import unittest
try:
    from io import BytesIO as IO
except ImportError:
    from StringIO import StringIO as IO
from server import MyHandlerSSL  # My BaseHTTPRequestHandler child


class TestableHandler(MyHandlerSSL):
    # On Python3, in socketserver.StreamRequestHandler, if this is
    # set it will use makefile() to produce the output stream. Otherwise,
    # it will use socketserver._SocketWriter, and we won't be able to get
    # to the data
    wbufsize = 1

    def finish(self):
        # Do not close self.wfile, so we can read its value
        self.wfile.flush()
        self.rfile.close()

    def date_time_string(self, timestamp=None):
        """ Mocked date time string """
        return 'DATETIME'

    def version_string(self):
        """ mock the server id """
        return 'BaseHTTP/x.x Python/x.x.x'


class MockSocket(object):
    def getsockname(self):
        return ('sockname',)


class MockRequest(object):
    _sock = MockSocket()

    def __init__(self, path):
        self._path = path

    def makefile(self, *args, **kwargs):
        if args[0] == 'rb':
            return IO(b"GET %s HTTP/1.0" % self._path)
        elif args[0] == 'wb':
            return IO(b'')
        else:
            raise ValueError("Unknown file type to make", args, kwargs)


class HTTPRequestHandlerTestCase(unittest.TestCase):
    maxDiff = None

    def _test(self, request):
        handler = TestableHandler(request, (0, 0), None)
        return handler.wfile.getvalue()

    def test_unauthenticated(self):
        self.assertEqual(
                self._test(MockRequest(b'/')),
                b"""HTTP/1.0 401 Unauthorized\r
Server: BaseHTTP/x.x Python/x.x.x\r
Date: DATETIME\r
WWW-Authenticate: Basic realm="MyRealm", charset="UTF-8"\r
Content-type: text/html\r
\r
Authentication Failed
Authentication Failed. Authorised Personnel Only.
"""
                )


def main():
    unittest.main()


if __name__ == "__main__":
    main()

The code I am testing returns a 401 Unauthorised for "/". Change the response as appopriate for your test case.