Method test_opener

Lib/test/test_io.py:925–932

(self)

            self.assertHasAttr(obj, "__dict__")

    def test_opener(self):
        with self.open(os_helper.TESTFN, "w", encoding="utf-8") as f:
            f.write("egg\n")
        fd = os.open(os_helper.TESTFN, os.O_RDONLY)
        def opener(path, flags):
            return fd
        with self.open("non-existent", "r", encoding="utf-8", opener=opener) as f:
            self.assertEqual(f.read(), "egg\n")

    def test_bad_opener_negative_1(self):
        # Issue #27066.