Thomas Wouters <thomas@xs4all.net>:

Test case for the pty module.

Lib/test/output/test_pty

+test_pty
+I wish to buy a fish license.
+For my pet fish, Eric.

Lib/test/test_pty.py

+import pty, os, sys, string
+from test_support import verbose, TestFailed
+
+TEST_STRING_1 = "I wish to buy a fish license."
+TEST_STRING_2 = "For my pet fish, Eric."
+TEST_STRING_3 = "And now for something completely different..."
+TEST_STRING_4 = "but you pronounce it throatwobbler mangrove."
+
+if verbose:
+    def debug(msg):
+        print msg
+else:
+    def debug(msg):
+        pass
+
+# Marginal testing of pty suite. Cannot do extensive 'do or fail' testing
+# because pty code is not too portable.
+
+try:
+    debug("Calling master_open()")
+    master_fd, slave_name = pty.master_open()
+    debug("Got master_fd '%d', slave_name '%s'"%(master_fd, slave_name))
+    debug("Calling slave_open(%s)"%`slave_name`)
+    slave_fd = pty.slave_open(slave_name)
+    debug("Got slave_fd '%d'"%slave_fd)
+except OSError:
+    # " An optional feature could not be imported " ... ?
+    raise ImportError, "Pseudo-terminals (seemingly) not functional."
+
+## # Please uncomment these if os.isatty() is added.
+## if not os.isatty(master_fd):
+##     raise TestFailed, "master_fd is not a tty"
+## if not os.isatty(slave_fd):
+##     raise TestFailed, "slave_fd is not a tty"
+
+debug("Writing to slave_fd")
+os.write(slave_fd, TEST_STRING_1) # should check return value
+print os.read(master_fd, 1024)
+
+os.write(slave_fd, TEST_STRING_2[:5])
+os.write(slave_fd, TEST_STRING_2[5:])
+print os.read(master_fd, 1024)
+
+os.close(slave_fd)
+os.close(master_fd)
+
+# basic pty passed.
+
+debug("calling pty.fork()")
+pid, master_fd = pty.fork()
+if pid == pty.CHILD:
+    ## # Please uncomment these when os.isatty() is added.
+    ## if not os.isatty(1):
+    ##     debug("Child's fd 1 is not a tty?!")
+    ##     os._exit(3)
+    try:
+        debug("In child, calling os.setsid()")
+        os.setsid()
+    except OSError:
+        # Good, we already were session leader
+        debug("OSError was raised.")
+        pass
+    except AttributeError:
+        # Have pty, but not setsid() ?
+        debug("AttributeError was raised.")
+        pass
+    except:
+        # We don't want this error to propagate, escape the call to
+        # os._exit(), and cause very peculiar behaviour in the calling
+        # regrtest.py !
+        debug("Some other error was raised.")
+        os._exit(1)
+    else:
+        debug("os.setsid() succeeded! (bad!)")
+        os._exit(2)
+    os._exit(4)
+else:
+    debug("Waiting for child (%d) to finish."%pid)
+    (pid, status) = os.waitpid(pid, 0)
+    debug("Child (%d) exited with status %d."%(pid, status))
+    if status / 256 == 1:
+        raise TestFailed, "Child raised an unexpected exception in os.setsid()"
+    elif status / 256 == 2:
+        raise TestFailed, "pty.fork() failed to make child a session leader."
+    elif status / 256 == 3:
+        raise TestFailed, "Child spawned by pty.fork() did not have a tty as stdout"
+    elif status / 256 <> 4:
+        raise TestFailed, "pty.fork() failed for unknown reasons:"
+        print os.read(master_fd, 65536)
+
+os.close(master_fd)
+
+# pty.fork() passed.
+