如何通过试用来测试扭曲的网络资源？

Question

我正在开发一个twisted.web 服务器 - 它由一些资源组成，除了渲染内容之外，还使用adbapi 来获取一些数据并将一些数据写入postgresql 数据库。我正在尝试弄清楚如何编写一个试用单元测试，该测试单元测试将在不使用网络的情况下测试资源渲染（换句话说：这将初始化资源，为其生成虚拟请求等）。

让我们假设 View 资源是一个简单的叶子，在 render_GET 中返回 NOT_DONE_YET 并修改 adbapi 以生成简单的文本作为结果。现在，我已经编写了这段无用的代码，但我无法想出如何使其实际初始化资源并产生一些合理的响应：

from twisted.trial import unittest
from myserv.views import View
from twisted.web.test.test_web import DummyRequest

class ExistingView(unittest.TestCase):
    def test_rendering(self):
        slug = "hello_world"
        view = View(slug)
        request = DummyRequest([''])
        output = view.render_GET(request)
        self.assertEqual(request.responseCode, 200)

输出是... 1.我也尝试过这样的方法：output = request。 render(view) 但相同的输出 = 1。为什么？我会非常感谢一些示例如何编写这样的单元测试！

Answer 1

下面是一个函数，它将渲染请求并将结果转换为渲染完成时触发的 Deferred：

def _render(resource, request):
    result = resource.render(request)
    if isinstance(result, str):
        request.write(result)
        request.finish()
        return succeed(None)
    elif result is server.NOT_DONE_YET:
        if request.finished:
            return succeed(None)
        else:
            return request.notifyFinish()
    else:
        raise ValueError("Unexpected return value: %r" % (result,))

它实际上在 Twisted Web 的测试套件中使用，但它是私有的，因为它本身没有单元测试。 ;)

您可以使用它来编写如下测试：

def test_rendering(self):
    slug = "hello_world"
    view = View(slug)
    request = DummyRequest([''])
    d = _render(view, request)
    def rendered(ignored):
        self.assertEquals(request.responseCode, 200)
        self.assertEquals("".join(request.written), "...")
        ...
    d.addCallback(rendered)
    return d

Answer 2

这是一个 DummierRequest 类，它解决了我几乎所有的问题。唯一剩下的就是它没有设置任何响应代码！为什么？

from twisted.web.test.test_web import DummyRequest
from twisted.web import server
from twisted.internet.defer import succeed
from twisted.internet import interfaces, reactor, protocol, address
from twisted.web.http_headers import _DictHeaders, Headers

class DummierRequest(DummyRequest):
    def __init__(self, postpath, session=None):
        DummyRequest.__init__(self, postpath, session)
        self.notifications = []
        self.received_cookies = {}
        self.requestHeaders = Headers()
        self.responseHeaders = Headers()
        self.cookies = [] # outgoing cookies

    def setHost(self, host, port, ssl=0):
        self._forceSSL = ssl
        self.requestHeaders.setRawHeaders("host", [host])
        self.host = address.IPv4Address("TCP", host, port)

    def addCookie(self, k, v, expires=None, domain=None, path=None, max_age=None, comment=None, secure=None):
        """
        Set an outgoing HTTP cookie.

        In general, you should consider using sessions instead of cookies, see
        L{twisted.web.server.Request.getSession} and the
        L{twisted.web.server.Session} class for details.
        """
        cookie = '%s=%s' % (k, v)
        if expires is not None:
            cookie = cookie +"; Expires=%s" % expires
        if domain is not None:
            cookie = cookie +"; Domain=%s" % domain
        if path is not None:
            cookie = cookie +"; Path=%s" % path
        if max_age is not None:
            cookie = cookie +"; Max-Age=%s" % max_age
        if comment is not None:
            cookie = cookie +"; Comment=%s" % comment
        if secure:
            cookie = cookie +"; Secure"
        self.cookies.append(cookie)

    def getCookie(self, key):
        """
        Get a cookie that was sent from the network.
        """
        return self.received_cookies.get(key)

    def getClientIP(self):
        """
        Return the IPv4 address of the client which made this request, if there
        is one, otherwise C{None}.
        """
        return "192.168.1.199"