Lib/test/test_pdb.py

# A test suite for pdb; at the moment, this only validates skipping of
# specified test modules (RFE #5142).

import imp
import sys
import os
import unittest
import subprocess
import textwrap

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


class PdbTestCase(unittest.TestCase):

    def run_pdb(self, script, commands):
        """Run 'script' lines with pdb and the pdb 'commands'."""
        filename = 'main.py'
        with open(filename, 'w') as f:
            f.write(textwrap.dedent(script))
        self.addCleanup(test_support.unlink, filename)
        cmd = [sys.executable, '-m', 'pdb', filename]
        stdout = stderr = None
        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                                   stdin=subprocess.PIPE,
                                   stderr=subprocess.STDOUT,
                                   )
        stdout, stderr = proc.communicate(commands)
        proc.stdout.close()
        proc.stdin.close()
        return stdout, stderr

    def test_issue13183(self):
        script = """
            from bar import bar

            def foo():
                bar()

            def nope():
                pass

            def foobar():
                foo()
                nope()

            foobar()
        """
        commands = """
            from bar import bar
            break bar
            continue
            step
            step
            quit
        """
        bar = """
            def bar():
                pass
        """
        with open('bar.py', 'w') as f:
            f.write(textwrap.dedent(bar))
        self.addCleanup(test_support.unlink, 'bar.py')
        self.addCleanup(test_support.unlink, 'bar.pyc')
        stdout, stderr = self.run_pdb(script, commands)
        self.assertTrue(
            any('main.py(5)foo()->None' in l for l in stdout.splitlines()),
            'Fail to step into the caller after a return')

    def test_issue16180(self):
        # A syntax error in the debuggee.
        script = "def f: pass\n"
        commands = ''
        expected = "SyntaxError:"
        stdout, stderr = self.run_pdb(script, commands)
        self.assertIn(expected, stdout,
            '\n\nExpected:\n{}\nGot:\n{}\n'
            'Fail to handle a syntax error in the debuggee.'
            .format(expected, stdout))


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 write(x):
    print x

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): write(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): write(i)
    0
    1
    2
    3
    4
    (Pdb) continue
    """

def test_pdb_breakpoint_commands():
    """Test basic commands related to breakpoints.

    >>> def test_function():
    ...     import pdb; pdb.Pdb().set_trace()
    ...     print(1)
    ...     print(2)
    ...     print(3)
    ...     print(4)

    First, need to clear bdb state that might be left over from previous tests.
    Otherwise, the new breakpoints might get assigned different numbers.

    >>> from bdb import Breakpoint
    >>> Breakpoint.next = 1
    >>> Breakpoint.bplist = {}
    >>> Breakpoint.bpbynumber = [None]

    Now test the breakpoint commands.  NORMALIZE_WHITESPACE is needed because
    the breakpoint list outputs a tab for the "stop only" and "ignore next"
    lines, which we don't want to put in here.

    >>> with PdbTestInput([  # doctest: +NORMALIZE_WHITESPACE
    ...     'break 3',
    ...     'disable 1',
    ...     'ignore 1 10',
    ...     'condition 1 1 < 2',
    ...     'break 4',
    ...     'break 4',
    ...     'break',
    ...     'clear 3',
    ...     'break',
    ...     'condition 1',
    ...     'enable 1',
    ...     'clear 1',
    ...     'commands 2',
    ...     'print 42',
    ...     'end',
    ...     'continue',  # will stop at breakpoint 2 (line 4)
    ...     'clear',     # clear all!
    ...     'y',
    ...     'tbreak 5',
    ...     'continue',  # will stop at temporary breakpoint
    ...     'break',     # make sure breakpoint is gone
    ...     'continue',
    ... ]):
    ...    test_function()
    > <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>(3)test_function()
    -> print(1)
    (Pdb) break 3
    Breakpoint 1 at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:3
    (Pdb) disable 1
    (Pdb) ignore 1 10
    Will ignore next 10 crossings of breakpoint 1.
    (Pdb) condition 1 1 < 2
    (Pdb) break 4
    Breakpoint 2 at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:4
    (Pdb) break 4
    Breakpoint 3 at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:4
    (Pdb) break
    Num Type         Disp Enb   Where
    1   breakpoint   keep no    at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:3
            stop only if 1 < 2
            ignore next 10 hits
    2   breakpoint   keep yes   at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:4
    3   breakpoint   keep yes   at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:4
    (Pdb) clear 3
    Deleted breakpoint 3
    (Pdb) break
    Num Type         Disp Enb   Where
    1   breakpoint   keep no    at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:3
            stop only if 1 < 2
            ignore next 10 hits
    2   breakpoint   keep yes   at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:4
    (Pdb) condition 1
    Breakpoint 1 is now unconditional.
    (Pdb) enable 1
    (Pdb) clear 1
    Deleted breakpoint 1
    (Pdb) commands 2
    (com) print 42
    (com) end
    (Pdb) continue
    1
    42
    > <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>(4)test_function()
    -> print(2)
    (Pdb) clear
    Clear all breaks? y
    (Pdb) tbreak 5
    Breakpoint 4 at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:5
    (Pdb) continue
    2
    Deleted breakpoint 4
    > <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>(5)test_function()
    -> print(3)
    (Pdb) break
    (Pdb) continue
    3
    4
    """


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

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

    >>> with PdbTestInput([
    ...     'step',
    ...     'continue',
    ... ]):
    ...     skip_module()
    > <doctest test.test_pdb.test_pdb_skip_modules[0]>(4)skip_module()
    -> string.lower('FOO')
    (Pdb) step
    --Return--
    > <doctest test.test_pdb.test_pdb_skip_modules[0]>(4)skip_module()->None
    -> string.lower('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' in 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 test_pdb_continue_in_bottomframe():
    """Test that "continue" and "next" work properly in bottom frame (issue #5294).

    >>> def test_function():
    ...     import pdb, sys; inst = pdb.Pdb()
    ...     inst.set_trace()
    ...     inst.botframe = sys._getframe()  # hackery to get the right botframe
    ...     print(1)
    ...     print(2)
    ...     print(3)
    ...     print(4)

    First, need to clear bdb state that might be left over from previous tests.
    Otherwise, the new breakpoints might get assigned different numbers.

    >>> from bdb import Breakpoint
    >>> Breakpoint.next = 1
    >>> Breakpoint.bplist = {}
    >>> Breakpoint.bpbynumber = [None]

    >>> with PdbTestInput([
    ...     'next',
    ...     'break 7',
    ...     'continue',
    ...     'next',
    ...     'continue',
    ...     'continue',
    ... ]):
    ...    test_function()
    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(4)test_function()
    -> inst.botframe = sys._getframe()  # hackery to get the right botframe
    (Pdb) next
    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(5)test_function()
    -> print(1)
    (Pdb) break 7
    Breakpoint 1 at <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>:7
    (Pdb) continue
    1
    2
    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(7)test_function()
    -> print(3)
    (Pdb) next
    3
    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(8)test_function()
    -> print(4)
    (Pdb) continue
    4
    """

class ModuleInitTester(unittest.TestCase):

    def test_filename_correct(self):
        """
        In issue 7750, it was found that if the filename has a sequence that
        resolves to an escape character in a Python string (such as \t), it
        will be treated as the escaped character.
        """
        # the test_fn must contain something like \t
        # on Windows, this will create 'test_mod.py' in the current directory.
        # on Unix, this will create '.\test_mod.py' in the current directory.
        test_fn = '.\\test_mod.py'
        code = 'print("testing pdb")'
        with open(test_fn, 'w') as f:
            f.write(code)
        self.addCleanup(os.remove, test_fn)
        cmd = [sys.executable, '-m', 'pdb', test_fn,]
        proc = subprocess.Popen(cmd,
            stdout=subprocess.PIPE,
            stdin=subprocess.PIPE,
            stderr=subprocess.STDOUT,
            )
        stdout, stderr = proc.communicate('quit\n')
        self.assertIn(code, stdout, "pdb munged the filename")


def test_main():
    from test import test_pdb
    test_support.run_doctest(test_pdb, verbosity=True)
    test_support.run_unittest(
        PdbTestCase,
        ModuleInitTester)

if __name__ == '__main__':
    test_main()