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test_debugger.py
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"""Tests for debugging machinery.
"""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import signal
import sys
import time
import warnings
from tempfile import NamedTemporaryFile
from subprocess import check_output, CalledProcessError, PIPE
import subprocess
from unittest.mock import patch
import builtins
import bdb
import nose.tools as nt
from IPython.core import debugger
#-----------------------------------------------------------------------------
# Helper classes, from CPython's Pdb test suite
#-----------------------------------------------------------------------------
class _FakeInput(object):
"""
A fake input stream for pdb's interactive debugger. Whenever a
line is read, print it (to simulate the user typing it), and then
return it. The set of lines to return is specified in the
constructor; they should not have trailing newlines.
"""
def __init__(self, lines):
self.lines = iter(lines)
def readline(self):
line = next(self.lines)
print(line)
return line+'\n'
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
#-----------------------------------------------------------------------------
# Tests
#-----------------------------------------------------------------------------
def test_longer_repr():
from reprlib import repr as trepr
a = '1234567890'* 7
ar = "'1234567890123456789012345678901234567890123456789012345678901234567890'"
a_trunc = "'123456789012...8901234567890'"
nt.assert_equal(trepr(a), a_trunc)
# The creation of our tracer modifies the repr module's repr function
# in-place, since that global is used directly by the stdlib's pdb module.
with warnings.catch_warnings():
warnings.simplefilter('ignore', DeprecationWarning)
debugger.Tracer()
nt.assert_equal(trepr(a), ar)
def test_ipdb_magics():
'''Test calling some IPython magics from ipdb.
First, set up some test functions and classes which we can inspect.
>>> class ExampleClass(object):
... """Docstring for ExampleClass."""
... def __init__(self):
... """Docstring for ExampleClass.__init__"""
... pass
... def __str__(self):
... return "ExampleClass()"
>>> def example_function(x, y, z="hello"):
... """Docstring for example_function."""
... pass
>>> old_trace = sys.gettrace()
Create a function which triggers ipdb.
>>> def trigger_ipdb():
... a = ExampleClass()
... debugger.Pdb().set_trace()
>>> with PdbTestInput([
... 'pdef example_function',
... 'pdoc ExampleClass',
... 'up',
... 'down',
... 'list',
... 'pinfo a',
... 'll',
... 'continue',
... ]):
... trigger_ipdb()
--Return--
None
> <doctest ...>(3)trigger_ipdb()
1 def trigger_ipdb():
2 a = ExampleClass()
----> 3 debugger.Pdb().set_trace()
<BLANKLINE>
ipdb> pdef example_function
example_function(x, y, z='hello')
ipdb> pdoc ExampleClass
Class docstring:
Docstring for ExampleClass.
Init docstring:
Docstring for ExampleClass.__init__
ipdb> up
> <doctest ...>(11)<module>()
7 'pinfo a',
8 'll',
9 'continue',
10 ]):
---> 11 trigger_ipdb()
<BLANKLINE>
ipdb> down
None
> <doctest ...>(3)trigger_ipdb()
1 def trigger_ipdb():
2 a = ExampleClass()
----> 3 debugger.Pdb().set_trace()
<BLANKLINE>
ipdb> list
1 def trigger_ipdb():
2 a = ExampleClass()
----> 3 debugger.Pdb().set_trace()
<BLANKLINE>
ipdb> pinfo a
Type: ExampleClass
String form: ExampleClass()
Namespace: Local...
Docstring: Docstring for ExampleClass.
Init docstring: Docstring for ExampleClass.__init__
ipdb> ll
1 def trigger_ipdb():
2 a = ExampleClass()
----> 3 debugger.Pdb().set_trace()
<BLANKLINE>
ipdb> continue
Restore previous trace function, e.g. for coverage.py
>>> sys.settrace(old_trace)
'''
def test_ipdb_magics2():
'''Test ipdb with a very short function.
>>> old_trace = sys.gettrace()
>>> def bar():
... pass
Run ipdb.
>>> with PdbTestInput([
... 'continue',
... ]):
... debugger.Pdb().runcall(bar)
> <doctest ...>(2)bar()
1 def bar():
----> 2 pass
<BLANKLINE>
ipdb> continue
Restore previous trace function, e.g. for coverage.py
>>> sys.settrace(old_trace)
'''
def can_quit():
'''Test that quit work in ipydb
>>> old_trace = sys.gettrace()
>>> def bar():
... pass
>>> with PdbTestInput([
... 'quit',
... ]):
... debugger.Pdb().runcall(bar)
> <doctest ...>(2)bar()
1 def bar():
----> 2 pass
<BLANKLINE>
ipdb> quit
Restore previous trace function, e.g. for coverage.py
>>> sys.settrace(old_trace)
'''
def can_exit():
'''Test that quit work in ipydb
>>> old_trace = sys.gettrace()
>>> def bar():
... pass
>>> with PdbTestInput([
... 'exit',
... ]):
... debugger.Pdb().runcall(bar)
> <doctest ...>(2)bar()
1 def bar():
----> 2 pass
<BLANKLINE>
ipdb> exit
Restore previous trace function, e.g. for coverage.py
>>> sys.settrace(old_trace)
'''
def test_interruptible_core_debugger():
"""The debugger can be interrupted.
The presumption is there is some mechanism that causes a KeyboardInterrupt
(this is implemented in ipykernel). We want to ensure the
KeyboardInterrupt cause debugging to cease.
"""
def raising_input(msg="", called=[0]):
called[0] += 1
if called[0] == 1:
raise KeyboardInterrupt()
else:
raise AssertionError("input() should only be called once!")
with patch.object(builtins, "input", raising_input):
debugger.InterruptiblePdb().set_trace()
# The way this test will fail is by set_trace() never exiting,
# resulting in a timeout by the test runner. The alternative
# implementation would involve a subprocess, but that adds issues with
# interrupting subprocesses that are rather complex, so it's simpler
# just to do it this way.