bpo-41818: Close file descriptors in test_openpty

When stdin is a TTY, the test added in commit c13d899
is expected to fail. However, when it failed, it did not close
its file descriptors. This is flagged by the refleak tests (but
only when stdin is a TTY, which doesn't seem to be the case on CI).

Author: encukou

Lib/test/test_pty.py

@@ -176,53 +176,54 @@ def test_openpty(self):
             # " An optional feature could not be imported " ... ?
             raise unittest.SkipTest("Pseudo-terminals (seemingly) not functional.")
 
-        self.assertTrue(os.isatty(slave_fd), "slave_fd is not a tty")
-
-        if mode:
-            self.assertEqual(tty.tcgetattr(slave_fd), mode,
-                             "openpty() failed to set slave termios")
-        if new_stdin_winsz:
-            self.assertEqual(_get_term_winsz(slave_fd), new_stdin_winsz,
-                             "openpty() failed to set slave window size")
-
-        # Solaris requires reading the fd before anything is returned.
-        # My guess is that since we open and close the slave fd
-        # in master_open(), we need to read the EOF.
-        #
-        # NOTE: the above comment is from an older version of the test;
-        # master_open() is not being used anymore.
-
-        # Ensure the fd is non-blocking in case there's nothing to read.
-        blocking = os.get_blocking(master_fd)
         try:
-            os.set_blocking(master_fd, False)
+            self.assertTrue(os.isatty(slave_fd), "slave_fd is not a tty")
+
+            if mode:
+                self.assertEqual(tty.tcgetattr(slave_fd), mode,
+                                "openpty() failed to set slave termios")
+            if new_stdin_winsz:
+                self.assertEqual(_get_term_winsz(slave_fd), new_stdin_winsz,
+                                "openpty() failed to set slave window size")
+
+            # Solaris requires reading the fd before anything is returned.
+            # My guess is that since we open and close the slave fd
+            # in master_open(), we need to read the EOF.
+            #
+            # NOTE: the above comment is from an older version of the test;
+            # master_open() is not being used anymore.
+
+            # Ensure the fd is non-blocking in case there's nothing to read.
+            blocking = os.get_blocking(master_fd)
             try:
-                s1 = os.read(master_fd, 1024)
-                self.assertEqual(b'', s1)
-            except OSError as e:
-                if e.errno != errno.EAGAIN:
-                    raise
+                os.set_blocking(master_fd, False)
+                try:
+                    s1 = os.read(master_fd, 1024)
+                    self.assertEqual(b'', s1)
+                except OSError as e:
+                    if e.errno != errno.EAGAIN:
+                        raise
+            finally:
+                # Restore the original flags.
+                os.set_blocking(master_fd, blocking)
+
+            debug("Writing to slave_fd")
+            os.write(slave_fd, TEST_STRING_1)
+            s1 = _readline(master_fd)
+            self.assertEqual(b'I wish to buy a fish license.\n',
+                            normalize_output(s1))
+
+            debug("Writing chunked output")
+            os.write(slave_fd, TEST_STRING_2[:5])
+            os.write(slave_fd, TEST_STRING_2[5:])
+            s2 = _readline(master_fd)
+            self.assertEqual(b'For my pet fish, Eric.\n', normalize_output(s2))
         finally:
-            # Restore the original flags.
-            os.set_blocking(master_fd, blocking)
-
-        debug("Writing to slave_fd")
-        os.write(slave_fd, TEST_STRING_1)
-        s1 = _readline(master_fd)
-        self.assertEqual(b'I wish to buy a fish license.\n',
-                         normalize_output(s1))
-
-        debug("Writing chunked output")
-        os.write(slave_fd, TEST_STRING_2[:5])
-        os.write(slave_fd, TEST_STRING_2[5:])
-        s2 = _readline(master_fd)
-        self.assertEqual(b'For my pet fish, Eric.\n', normalize_output(s2))
-
-        os.close(slave_fd)
-        # closing master_fd can raise a SIGHUP if the process is
-        # the session leader: we installed a SIGHUP signal handler
-        # to ignore this signal.
-        os.close(master_fd)
+            os.close(slave_fd)
+            # closing master_fd can raise a SIGHUP if the process is
+            # the session leader: we installed a SIGHUP signal handler
+            # to ignore this signal.
+            os.close(master_fd)
 
     def test_fork(self):
         debug("calling pty.fork()")