    def test_file(self, tmpdir):
        filename = tmpdir / 'foo'
        filename.ensure()
        url = QUrl.fromLocalFile(str(filename))
        req = QNetworkRequest(url)
        reply = filescheme.handler(req)
        assert reply is None
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.