def METHOD_NAME(self):
    """
    L{NameVirtualHost.render} returns the result of rendering the
    instance's C{default} if it is not L{None} and there is no host
    matching the value of the I{Host} header in the request.
    """
    virtualHostResource = NameVirtualHost()
    virtualHostResource.default = Data(b"correct data", "")
    request = DummyRequest([b""])
    request.requestHeaders.addRawHeader(b"host", b"example.com")
    d = _render(virtualHostResource, request)
    def cbRendered(ignored):
        self.assertEqual(b"".join(request.written), b"correct data")
    d.addCallback(cbRendered)
    return d