Mini Shell

'''Test warnings replacement in pyshell.py and run.py.

This file could be expanded to include traceback overrides
(in same two modules). If so, change name.
Revise if output destination changes (http://bugs.python.org/issue18318).
Make sure warnings module is left unaltered (http://bugs.python.org/issue18081).
'''
from idlelib import run
from idlelib import pyshell as shell
import unittest
from test.support import captured_stderr
import warnings

# Try to capture default showwarning before Idle modules are imported.
showwarning = warnings.showwarning
# But if we run this file within idle, we are in the middle of the run.main loop
# and default showwarnings has already been replaced.
running_in_idle = 'idle' in showwarning.__name__

# The following was generated from pyshell.idle_formatwarning
# and checked as matching expectation.
idlemsg = '''
Warning (from warnings module):
  File "test_warning.py", line 99
    Line of code
UserWarning: Test
'''
shellmsg = idlemsg + ">>> "


class RunWarnTest(unittest.TestCase):

    @unittest.skipIf(running_in_idle, "Does not work when run within Idle.")
    def test_showwarnings(self):
        self.assertIs(warnings.showwarning, showwarning)
        run.capture_warnings(True)
        self.assertIs(warnings.showwarning, run.idle_showwarning_subproc)
        run.capture_warnings(False)
        self.assertIs(warnings.showwarning, showwarning)

    def test_run_show(self):
        with captured_stderr() as f:
            run.idle_showwarning_subproc(
                    'Test', UserWarning, 'test_warning.py', 99, f, 'Line of code')
            # The following uses .splitlines to erase line-ending differences
            self.assertEqual(idlemsg.splitlines(), f.getvalue().splitlines())


class ShellWarnTest(unittest.TestCase):

    @unittest.skipIf(running_in_idle, "Does not work when run within Idle.")
    def test_showwarnings(self):
        self.assertIs(warnings.showwarning, showwarning)
        shell.capture_warnings(True)
        self.assertIs(warnings.showwarning, shell.idle_showwarning)
        shell.capture_warnings(False)
        self.assertIs(warnings.showwarning, showwarning)

    def test_idle_formatter(self):
        # Will fail if format changed without regenerating idlemsg
        s = shell.idle_formatwarning(
                'Test', UserWarning, 'test_warning.py', 99, 'Line of code')
        self.assertEqual(idlemsg, s)

    def test_shell_show(self):
        with captured_stderr() as f:
            shell.idle_showwarning(
                    'Test', UserWarning, 'test_warning.py', 99, f, 'Line of code')
            self.assertEqual(shellmsg.splitlines(), f.getvalue().splitlines())


if __name__ == '__main__':
    unittest.main(verbosity=2)