test_csv.py 文件源码

def test_write_fields_not_in_fieldnames(self):
        fd, name = tempfile.mkstemp()
        fileobj = os.fdopen(fd, "w+b")
        try:
            writer = csv.DictWriter(fileobj, fieldnames = ["f1", "f2", "f3"])
            # Of special note is the non-string key (issue 19449)
            with self.assertRaises(ValueError) as cx:
                writer.writerow({"f4": 10, "f2": "spam", 1: "abc"})
            exception = str(cx.exception)
            self.assertIn("fieldnames", exception)
            self.assertIn("'f4'", exception)
            self.assertNotIn("'f2'", exception)
            self.assertIn("1", exception)
        finally:
            fileobj.close()
            os.unlink(name)