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

Here's one approach I came up with to mock the server. Note that this should be compatible with both Python 2 and python 3. The only issue is that I can't find a way to access the result of the GET request, but at least the test will catch any exceptions it comes across!

try:
    # Python 2.x
    import BaseHTTPServer as server
    from StringIO import StringIO as IO
except ImportError:
    # Python 3.x
    from http import server
    from io import BytesIO as IO


class MyHandler(server.BaseHTTPRequestHandler):
    """Custom handler to be tested"""
    def do_GET(self):
        # print just to confirm that this method is being called
        print("executing do_GET") # just to confirm...

        self.send_response(200)
        self.send_header("Content-type", "text/html")
        self.end_headers()

        # Here's where all the complicated logic is done to generate HTML.
        # For clarity here, replace with a simple stand-in:
        html = "
hello world
"

        self.wfile.write(html.encode())


def test_handler():
    """Test the custom HTTP request handler by mocking a server"""
    class MockRequest(object):
        def makefile(self, *args, **kwargs):
            return IO(b"GET /")

    class MockServer(object):
        def __init__(self, ip_port, Handler):
            handler = Handler(MockRequest(), ip_port, self)

    # The GET request will be sent here
    # and any exceptions will be propagated through.
    server = MockServer(('0.0.0.0', 8888), MyHandler)


test_handler()