Test for filling stderr buffer.

IPython/utils/tests/test_process.py

@@ -1,199 +1,210 b''
 # encoding: utf-8
 """
 Tests for platutils.py
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import sys
 import os
 import time
 from _thread import interrupt_main  # Py 3
 import threading
 from unittest import SkipTest
 
 import nose.tools as nt
 
 from IPython.utils.process import (find_cmd, FindCmdError, arg_split,
                                    system, getoutput, getoutputerror,
                                    get_output_error_code)
+from IPython.utils.capture import capture_output
 from IPython.testing import decorators as dec
 from IPython.testing import tools as tt
 
 python = os.path.basename(sys.executable)
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 
 @dec.skip_win32
 def test_find_cmd_ls():
     """Make sure we can find the full path to ls."""
     path = find_cmd('ls')
     nt.assert_true(path.endswith('ls'))
 
     
 def has_pywin32():
     try:
         import win32api
     except ImportError:
         return False
     return True
 
 
 @dec.onlyif(has_pywin32, "This test requires win32api to run")
 def test_find_cmd_pythonw():
     """Try to find pythonw on Windows."""
     path = find_cmd('pythonw')
     assert path.lower().endswith('pythonw.exe'), path
 
 
 @dec.onlyif(lambda : sys.platform != 'win32' or has_pywin32(),
             "This test runs on posix or in win32 with win32api installed")
 def test_find_cmd_fail():
     """Make sure that FindCmdError is raised if we can't find the cmd."""
     nt.assert_raises(FindCmdError,find_cmd,'asdfasdf')
 
     
 @dec.skip_win32
 def test_arg_split():
     """Ensure that argument lines are correctly split like in a shell."""
     tests = [['hi', ['hi']],
              [u'hi', [u'hi']],
              ['hello there', ['hello', 'there']],
              # \u01ce == \N{LATIN SMALL LETTER A WITH CARON}
              # Do not use \N because the tests crash with syntax error in
              # some cases, for example windows python2.6.
              [u'h\u01cello', [u'h\u01cello']],
              ['something "with quotes"', ['something', '"with quotes"']],
              ]
     for argstr, argv in tests:
         nt.assert_equal(arg_split(argstr), argv)
     
 @dec.skip_if_not_win32
 def test_arg_split_win32():
     """Ensure that argument lines are correctly split like in a shell."""
     tests = [['hi', ['hi']],
              [u'hi', [u'hi']],
              ['hello there', ['hello', 'there']],
              [u'h\u01cello', [u'h\u01cello']],
              ['something "with quotes"', ['something', 'with quotes']],
              ]
     for argstr, argv in tests:
         nt.assert_equal(arg_split(argstr), argv)
 
 
 class SubProcessTestCase(tt.TempFileMixin):
     def setUp(self):
         """Make a valid python temp file."""
         lines = [ "import sys",
                  "print('on stdout', end='', file=sys.stdout)",
                  "print('on stderr', end='', file=sys.stderr)",
                  "sys.stdout.flush()",
                  "sys.stderr.flush()"]
         self.mktmp('\n'.join(lines))
 
     def test_system(self):
         status = system('%s "%s"' % (python, self.fname))
         self.assertEqual(status, 0)
 
     def test_system_quotes(self):
         status = system('%s -c "import sys"' % python)
         self.assertEqual(status, 0)
 
     def assert_interrupts(self, command):
         """
         Interrupt a subprocess after a second.
         """
         if threading.main_thread() != threading.current_thread():
             raise nt.SkipTest("Can't run this test if not in main thread.")
 
         def interrupt():
             # Wait for subprocess to start:
             time.sleep(0.5)
             interrupt_main()
 
         threading.Thread(target=interrupt).start()
         start = time.time()
         try:
             result = command()
         except KeyboardInterrupt:
             # Success!
             return
         end = time.time()
         self.assertTrue(
             end - start < 2, "Process didn't die quickly: %s" % (end - start)
         )
         return result
 
     def test_system_interrupt(self):
         """
         When interrupted in the way ipykernel interrupts IPython, the
         subprocess is interrupted.
         """
         def command():
             return system('%s -c "import time; time.sleep(5)"' % python)
 
         status = self.assert_interrupts(command)
         self.assertNotEqual(
             status, 0, "The process wasn't interrupted. Status: %s" % (status,)
         )
 
+    def test_stderr_while_stdout_open(self):
+        """
+        If lots of data is written to stderr while stdout is still open, enough
+        data to fill the pipe buffer in fact, the process still exits (i.e.
+        there is no deadlock).
+        """
+        with capture_output(display=False):
+            system(("%s -c 'import sys\nfor i in range(2000): " +
+                    "sys.stderr.write(\" \" * 100 + \"\\n\")'") % (python,))
+
     def test_getoutput(self):
         out = getoutput('%s "%s"' % (python, self.fname))
         # we can't rely on the order the line buffered streams are flushed
         try:
             self.assertEqual(out, 'on stderron stdout')
         except AssertionError:
             self.assertEqual(out, 'on stdouton stderr')
 
     def test_getoutput_interrupt(self):
         """
         When interrupted in the way ipykernel interrupts IPython, the
         subprocess is interrupted.
         """
         raise SkipTest("This fails on POSIX too, revisit in future.")
         def command():
             return getoutput('%s -c "import time; time.sleep(5)"' % (python, ))
 
         self.assert_interrupts(command)
 
     def test_getoutput_quoted(self):
         out = getoutput('%s -c "print (1)"' % python)
         self.assertEqual(out.strip(), '1')
 
     #Invalid quoting on windows
     @dec.skip_win32
     def test_getoutput_quoted2(self):
         out = getoutput("%s -c 'print (1)'" % python)
         self.assertEqual(out.strip(), '1')
         out = getoutput("%s -c 'print (\"1\")'" % python)
         self.assertEqual(out.strip(), '1')
 
     def test_getoutput_error(self):
         out, err = getoutputerror('%s "%s"' % (python, self.fname))
         self.assertEqual(out, 'on stdout')
         self.assertEqual(err, 'on stderr')
 
     def test_get_output_error_code(self):
         quiet_exit = '%s -c "import sys; sys.exit(1)"' % python
         out, err, code = get_output_error_code(quiet_exit)
         self.assertEqual(out, '')
         self.assertEqual(err, '')
         self.assertEqual(code, 1)
         out, err, code = get_output_error_code('%s "%s"' % (python, self.fname))
         self.assertEqual(out, 'on stdout')
         self.assertEqual(err, 'on stderr')
         self.assertEqual(code, 0)