Lib/test/test_pdb.py

# A test suite for pdb; not very comprehensive at the moment.

import imp
import sys

from test import support
# This little helper class is essential for testing pdb under doctest.
from test.test_doctest import _FakeInput


class PdbTestInput(object):
    """Context manager that makes testing Pdb in doctests easier."""

    def __init__(self, input):
        self.input = input

    def __enter__(self):
        self.real_stdin = sys.stdin
        sys.stdin = _FakeInput(self.input)

    def __exit__(self, *exc):
        sys.stdin = self.real_stdin


def test_pdb_displayhook():
    """This tests the custom displayhook for pdb.

    >>> def test_function(foo, bar):
    ...     import pdb; pdb.Pdb().set_trace()
    ...     pass

    >>> with PdbTestInput([
    ...     'foo',
    ...     'bar',
    ...     'for i in range(5): print(i)',
    ...     'continue',
    ... ]):
    ...     test_function(1, None)
    > <doctest test.test_pdb.test_pdb_displayhook[0]>(3)test_function()
    -> pass
    (Pdb) foo
    1
    (Pdb) bar
    (Pdb) for i in range(5): print(i)
    0
    1
    2
    3
    4
    (Pdb) continue
    """


def test_pdb_skip_modules():
    """This illustrates the simple case of module skipping.

    >>> def skip_module():
    ...     import string
    ...     import pdb; pdb.Pdb(skip=['stri*']).set_trace()
    ...     string.capwords('FOO')

    >>> with PdbTestInput([
    ...     'step',
    ...     'continue',
    ... ]):
    ...     skip_module()
    > <doctest test.test_pdb.test_pdb_skip_modules[0]>(4)skip_module()
    -> string.capwords('FOO')
    (Pdb) step
    --Return--
    > <doctest test.test_pdb.test_pdb_skip_modules[0]>(4)skip_module()->None
    -> string.capwords('FOO')
    (Pdb) continue
    """


# Module for testing skipping of module that makes a callback
mod = imp.new_module('module_to_skip')
exec('def foo_pony(callback): x = 1; callback(); return None', mod.__dict__)


def test_pdb_skip_modules_with_callback():
    """This illustrates skipping of modules that call into other code.

    >>> def skip_module():
    ...     def callback():
    ...         return None
    ...     import pdb; pdb.Pdb(skip=['module_to_skip*']).set_trace()
    ...     mod.foo_pony(callback)

    >>> with PdbTestInput([
    ...     'step',
    ...     'step',
    ...     'step',
    ...     'step',
    ...     'step',
    ...     'continue',
    ... ]):
    ...     skip_module()
    ...     pass  # provides something to "step" to
    > <doctest test.test_pdb.test_pdb_skip_modules_with_callback[0]>(5)skip_module()
    -> mod.foo_pony(callback)
    (Pdb) step
    --Call--
    > <doctest test.test_pdb.test_pdb_skip_modules_with_callback[0]>(2)callback()
    -> def callback():
    (Pdb) step
    > <doctest test.test_pdb.test_pdb_skip_modules_with_callback[0]>(3)callback()
    -> return None
    (Pdb) step
    --Return--
    > <doctest test.test_pdb.test_pdb_skip_modules_with_callback[0]>(3)callback()->None
    -> return None
    (Pdb) step
    --Return--
    > <doctest test.test_pdb.test_pdb_skip_modules_with_callback[0]>(5)skip_module()->None
    -> mod.foo_pony(callback)
    (Pdb) step
    > <doctest test.test_pdb.test_pdb_skip_modules_with_callback[1]>(10)<module>()
    -> pass  # provides something to "step" to
    (Pdb) continue
    """


def pdb_invoke(method, arg):
    """Run pdb.method(arg)."""
    import pdb; getattr(pdb, method)(arg)


def test_pdb_run_with_incorrect_argument():
    """Testing run and runeval with incorrect first argument.

    >>> pti = PdbTestInput(['continue',])
    >>> with pti:
    ...     pdb_invoke('run', lambda x: x)
    Traceback (most recent call last):
    TypeError: exec() arg 1 must be a string, bytes or code object

    >>> with pti:
    ...     pdb_invoke('runeval', lambda x: x)
    Traceback (most recent call last):
    TypeError: eval() arg 1 must be a string, bytes or code object
    """


def test_pdb_run_with_code_object():
    """Testing run and runeval with code object as a first argument.

    >>> with PdbTestInput(['step','x', 'continue']):
    ...     pdb_invoke('run', compile('x=1', '<string>', 'exec'))
    > <string>(1)<module>()
    (Pdb) step
    --Return--
    > <string>(1)<module>()->None
    (Pdb) x
    1
    (Pdb) continue

    >>> with PdbTestInput(['x', 'continue']):
    ...     x=0
    ...     pdb_invoke('runeval', compile('x+1', '<string>', 'eval'))
    > <string>(1)<module>()->None
    (Pdb) x
    1
    (Pdb) continue
    """


def test_main():
    from test import test_pdb
    support.run_doctest(test_pdb, verbosity=True)


if __name__ == '__main__':
    test_main()