Python：如何对自定义HTTP请求处理器进行单元测试？
我有一个自定义的HTTP请求处理器，可以简单地理解成下面这样的代码：
# Python 3:
from http import server
class MyHandler(server.BaseHTTPRequestHandler):
def do_GET(self):
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 = "<html><p>hello world</p></html>"
self.wfile.write(html.encode())
我想对这个处理器进行单元测试，也就是确保我的 do_GET 方法能正常执行，没有任何错误，而不需要真正启动一个网络服务器。有没有什么简单的方法可以模拟 SimpleHTTPServer，让我可以测试这段代码呢？
3 个回答
2
这件事有点复杂，主要看你想多深入了解BaseHTTPRequestHandler的行为，以便定义你的单元测试。最基本的来说，我觉得你可以参考一下mock库中的这个例子：
>>> from mock import MagicMock
>>> thing = ProductionClass()
>>> thing.method = MagicMock(return_value=3)
>>> thing.method(3, 4, 5, key='value')
3
>>> thing.method.assert_called_with(3, 4, 5, key='value')
如果你知道你的类会调用BaseHTTPRequestHandler中的哪些方法，你就可以模拟这些方法的返回结果，让它们变得合适。这当然会变得相当复杂，具体取决于你想测试多少种不同类型的服务器响应。
6
在jakevdp的回答基础上，我也成功地检查了输出：
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
<html><head><title>Authentication Failed</title></html><body><h1>Authentication Failed</h1><p>Authentication Failed. Authorised Personnel Only.</p></body></html>"""
)
def main():
unittest.main()
if __name__ == "__main__":
main()
我正在测试的代码对“/”这个请求返回了401未授权的错误。你可以根据自己的测试情况，修改这个响应。
4
这是我想到的一种模拟服务器的方法。请注意，这种方法在Python 2和Python 3中都可以使用。唯一的问题是我找不到获取GET请求结果的方法，不过至少测试可以捕捉到遇到的任何异常！
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 = "<html><p>hello world</p></html>"
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()