test_ok1/_pytest/capture.py

571 lines
17 KiB
Python

"""
per-test stdout/stderr capturing mechanism.
"""
from __future__ import absolute_import, division, print_function
import contextlib
import sys
import os
import io
from io import UnsupportedOperation
from tempfile import TemporaryFile
import py
import pytest
from _pytest.compat import CaptureIO
unicode = py.builtin.text
patchsysdict = {0: 'stdin', 1: 'stdout', 2: 'stderr'}
def pytest_addoption(parser):
group = parser.getgroup("general")
group._addoption(
'--capture', action="store",
default="fd" if hasattr(os, "dup") else "sys",
metavar="method", choices=['fd', 'sys', 'no'],
help="per-test capturing method: one of fd|sys|no.")
group._addoption(
'-s', action="store_const", const="no", dest="capture",
help="shortcut for --capture=no.")
@pytest.hookimpl(hookwrapper=True)
def pytest_load_initial_conftests(early_config, parser, args):
ns = early_config.known_args_namespace
if ns.capture == "fd":
_py36_windowsconsoleio_workaround()
_colorama_workaround()
_readline_workaround()
pluginmanager = early_config.pluginmanager
capman = CaptureManager(ns.capture)
pluginmanager.register(capman, "capturemanager")
# make sure that capturemanager is properly reset at final shutdown
early_config.add_cleanup(capman.reset_capturings)
# make sure logging does not raise exceptions at the end
def silence_logging_at_shutdown():
if "logging" in sys.modules:
sys.modules["logging"].raiseExceptions = False
early_config.add_cleanup(silence_logging_at_shutdown)
# finally trigger conftest loading but while capturing (issue93)
capman.init_capturings()
outcome = yield
out, err = capman.suspendcapture()
if outcome.excinfo is not None:
sys.stdout.write(out)
sys.stderr.write(err)
class CaptureManager:
def __init__(self, method):
self._method = method
def _getcapture(self, method):
if method == "fd":
return MultiCapture(out=True, err=True, Capture=FDCapture)
elif method == "sys":
return MultiCapture(out=True, err=True, Capture=SysCapture)
elif method == "no":
return MultiCapture(out=False, err=False, in_=False)
else:
raise ValueError("unknown capturing method: %r" % method)
def init_capturings(self):
assert not hasattr(self, "_capturing")
self._capturing = self._getcapture(self._method)
self._capturing.start_capturing()
def reset_capturings(self):
cap = self.__dict__.pop("_capturing", None)
if cap is not None:
cap.pop_outerr_to_orig()
cap.stop_capturing()
def resumecapture(self):
self._capturing.resume_capturing()
def suspendcapture(self, in_=False):
self.deactivate_funcargs()
cap = getattr(self, "_capturing", None)
if cap is not None:
try:
outerr = cap.readouterr()
finally:
cap.suspend_capturing(in_=in_)
return outerr
def activate_funcargs(self, pyfuncitem):
capfuncarg = pyfuncitem.__dict__.pop("_capfuncarg", None)
if capfuncarg is not None:
capfuncarg._start()
self._capfuncarg = capfuncarg
def deactivate_funcargs(self):
capfuncarg = self.__dict__.pop("_capfuncarg", None)
if capfuncarg is not None:
capfuncarg.close()
@pytest.hookimpl(hookwrapper=True)
def pytest_make_collect_report(self, collector):
if isinstance(collector, pytest.File):
self.resumecapture()
outcome = yield
out, err = self.suspendcapture()
rep = outcome.get_result()
if out:
rep.sections.append(("Captured stdout", out))
if err:
rep.sections.append(("Captured stderr", err))
else:
yield
@pytest.hookimpl(hookwrapper=True)
def pytest_runtest_setup(self, item):
self.resumecapture()
yield
self.suspendcapture_item(item, "setup")
@pytest.hookimpl(hookwrapper=True)
def pytest_runtest_call(self, item):
self.resumecapture()
self.activate_funcargs(item)
yield
# self.deactivate_funcargs() called from suspendcapture()
self.suspendcapture_item(item, "call")
@pytest.hookimpl(hookwrapper=True)
def pytest_runtest_teardown(self, item):
self.resumecapture()
yield
self.suspendcapture_item(item, "teardown")
@pytest.hookimpl(tryfirst=True)
def pytest_keyboard_interrupt(self, excinfo):
self.reset_capturings()
@pytest.hookimpl(tryfirst=True)
def pytest_internalerror(self, excinfo):
self.reset_capturings()
def suspendcapture_item(self, item, when, in_=False):
out, err = self.suspendcapture(in_=in_)
item.add_report_section(when, "stdout", out)
item.add_report_section(when, "stderr", err)
error_capsysfderror = "cannot use capsys and capfd at the same time"
@pytest.fixture
def capsys(request):
"""Enable capturing of writes to sys.stdout/sys.stderr and make
captured output available via ``capsys.readouterr()`` method calls
which return a ``(out, err)`` tuple.
"""
if "capfd" in request.fixturenames:
raise request.raiseerror(error_capsysfderror)
request.node._capfuncarg = c = CaptureFixture(SysCapture, request)
return c
@pytest.fixture
def capfd(request):
"""Enable capturing of writes to file descriptors 1 and 2 and make
captured output available via ``capfd.readouterr()`` method calls
which return a ``(out, err)`` tuple.
"""
if "capsys" in request.fixturenames:
request.raiseerror(error_capsysfderror)
if not hasattr(os, 'dup'):
pytest.skip("capfd funcarg needs os.dup")
request.node._capfuncarg = c = CaptureFixture(FDCapture, request)
return c
class CaptureFixture:
def __init__(self, captureclass, request):
self.captureclass = captureclass
self.request = request
def _start(self):
self._capture = MultiCapture(out=True, err=True, in_=False,
Capture=self.captureclass)
self._capture.start_capturing()
def close(self):
cap = self.__dict__.pop("_capture", None)
if cap is not None:
self._outerr = cap.pop_outerr_to_orig()
cap.stop_capturing()
def readouterr(self):
try:
return self._capture.readouterr()
except AttributeError:
return self._outerr
@contextlib.contextmanager
def disabled(self):
capmanager = self.request.config.pluginmanager.getplugin('capturemanager')
capmanager.suspendcapture_item(self.request.node, "call", in_=True)
try:
yield
finally:
capmanager.resumecapture()
def safe_text_dupfile(f, mode, default_encoding="UTF8"):
""" return a open text file object that's a duplicate of f on the
FD-level if possible.
"""
encoding = getattr(f, "encoding", None)
try:
fd = f.fileno()
except Exception:
if "b" not in getattr(f, "mode", "") and hasattr(f, "encoding"):
# we seem to have a text stream, let's just use it
return f
else:
newfd = os.dup(fd)
if "b" not in mode:
mode += "b"
f = os.fdopen(newfd, mode, 0) # no buffering
return EncodedFile(f, encoding or default_encoding)
class EncodedFile(object):
errors = "strict" # possibly needed by py3 code (issue555)
def __init__(self, buffer, encoding):
self.buffer = buffer
self.encoding = encoding
def write(self, obj):
if isinstance(obj, unicode):
obj = obj.encode(self.encoding, "replace")
self.buffer.write(obj)
def writelines(self, linelist):
data = ''.join(linelist)
self.write(data)
@property
def name(self):
"""Ensure that file.name is a string."""
return repr(self.buffer)
def __getattr__(self, name):
return getattr(object.__getattribute__(self, "buffer"), name)
class MultiCapture(object):
out = err = in_ = None
def __init__(self, out=True, err=True, in_=True, Capture=None):
if in_:
self.in_ = Capture(0)
if out:
self.out = Capture(1)
if err:
self.err = Capture(2)
def start_capturing(self):
if self.in_:
self.in_.start()
if self.out:
self.out.start()
if self.err:
self.err.start()
def pop_outerr_to_orig(self):
""" pop current snapshot out/err capture and flush to orig streams. """
out, err = self.readouterr()
if out:
self.out.writeorg(out)
if err:
self.err.writeorg(err)
return out, err
def suspend_capturing(self, in_=False):
if self.out:
self.out.suspend()
if self.err:
self.err.suspend()
if in_ and self.in_:
self.in_.suspend()
self._in_suspended = True
def resume_capturing(self):
if self.out:
self.out.resume()
if self.err:
self.err.resume()
if hasattr(self, "_in_suspended"):
self.in_.resume()
del self._in_suspended
def stop_capturing(self):
""" stop capturing and reset capturing streams """
if hasattr(self, '_reset'):
raise ValueError("was already stopped")
self._reset = True
if self.out:
self.out.done()
if self.err:
self.err.done()
if self.in_:
self.in_.done()
def readouterr(self):
""" return snapshot unicode value of stdout/stderr capturings. """
return (self.out.snap() if self.out is not None else "",
self.err.snap() if self.err is not None else "")
class NoCapture:
__init__ = start = done = suspend = resume = lambda *args: None
class FDCapture:
""" Capture IO to/from a given os-level filedescriptor. """
def __init__(self, targetfd, tmpfile=None):
self.targetfd = targetfd
try:
self.targetfd_save = os.dup(self.targetfd)
except OSError:
self.start = lambda: None
self.done = lambda: None
else:
if targetfd == 0:
assert not tmpfile, "cannot set tmpfile with stdin"
tmpfile = open(os.devnull, "r")
self.syscapture = SysCapture(targetfd)
else:
if tmpfile is None:
f = TemporaryFile()
with f:
tmpfile = safe_text_dupfile(f, mode="wb+")
if targetfd in patchsysdict:
self.syscapture = SysCapture(targetfd, tmpfile)
else:
self.syscapture = NoCapture()
self.tmpfile = tmpfile
self.tmpfile_fd = tmpfile.fileno()
def __repr__(self):
return "<FDCapture %s oldfd=%s>" % (self.targetfd, self.targetfd_save)
def start(self):
""" Start capturing on targetfd using memorized tmpfile. """
try:
os.fstat(self.targetfd_save)
except (AttributeError, OSError):
raise ValueError("saved filedescriptor not valid anymore")
os.dup2(self.tmpfile_fd, self.targetfd)
self.syscapture.start()
def snap(self):
f = self.tmpfile
f.seek(0)
res = f.read()
if res:
enc = getattr(f, "encoding", None)
if enc and isinstance(res, bytes):
res = py.builtin._totext(res, enc, "replace")
f.truncate(0)
f.seek(0)
return res
return ''
def done(self):
""" stop capturing, restore streams, return original capture file,
seeked to position zero. """
targetfd_save = self.__dict__.pop("targetfd_save")
os.dup2(targetfd_save, self.targetfd)
os.close(targetfd_save)
self.syscapture.done()
self.tmpfile.close()
def suspend(self):
self.syscapture.suspend()
os.dup2(self.targetfd_save, self.targetfd)
def resume(self):
self.syscapture.resume()
os.dup2(self.tmpfile_fd, self.targetfd)
def writeorg(self, data):
""" write to original file descriptor. """
if py.builtin._istext(data):
data = data.encode("utf8") # XXX use encoding of original stream
os.write(self.targetfd_save, data)
class SysCapture:
def __init__(self, fd, tmpfile=None):
name = patchsysdict[fd]
self._old = getattr(sys, name)
self.name = name
if tmpfile is None:
if name == "stdin":
tmpfile = DontReadFromInput()
else:
tmpfile = CaptureIO()
self.tmpfile = tmpfile
def start(self):
setattr(sys, self.name, self.tmpfile)
def snap(self):
f = self.tmpfile
res = f.getvalue()
f.truncate(0)
f.seek(0)
return res
def done(self):
setattr(sys, self.name, self._old)
del self._old
self.tmpfile.close()
def suspend(self):
setattr(sys, self.name, self._old)
def resume(self):
setattr(sys, self.name, self.tmpfile)
def writeorg(self, data):
self._old.write(data)
self._old.flush()
class DontReadFromInput:
"""Temporary stub class. Ideally when stdin is accessed, the
capturing should be turned off, with possibly all data captured
so far sent to the screen. This should be configurable, though,
because in automated test runs it is better to crash than
hang indefinitely.
"""
encoding = None
def read(self, *args):
raise IOError("reading from stdin while output is captured")
readline = read
readlines = read
__iter__ = read
def fileno(self):
raise UnsupportedOperation("redirected stdin is pseudofile, "
"has no fileno()")
def isatty(self):
return False
def close(self):
pass
@property
def buffer(self):
if sys.version_info >= (3, 0):
return self
else:
raise AttributeError('redirected stdin has no attribute buffer')
def _colorama_workaround():
"""
Ensure colorama is imported so that it attaches to the correct stdio
handles on Windows.
colorama uses the terminal on import time. So if something does the
first import of colorama while I/O capture is active, colorama will
fail in various ways.
"""
if not sys.platform.startswith('win32'):
return
try:
import colorama # noqa
except ImportError:
pass
def _readline_workaround():
"""
Ensure readline is imported so that it attaches to the correct stdio
handles on Windows.
Pdb uses readline support where available--when not running from the Python
prompt, the readline module is not imported until running the pdb REPL. If
running pytest with the --pdb option this means the readline module is not
imported until after I/O capture has been started.
This is a problem for pyreadline, which is often used to implement readline
support on Windows, as it does not attach to the correct handles for stdout
and/or stdin if they have been redirected by the FDCapture mechanism. This
workaround ensures that readline is imported before I/O capture is setup so
that it can attach to the actual stdin/out for the console.
See https://github.com/pytest-dev/pytest/pull/1281
"""
if not sys.platform.startswith('win32'):
return
try:
import readline # noqa
except ImportError:
pass
def _py36_windowsconsoleio_workaround():
"""
Python 3.6 implemented unicode console handling for Windows. This works
by reading/writing to the raw console handle using
``{Read,Write}ConsoleW``.
The problem is that we are going to ``dup2`` over the stdio file
descriptors when doing ``FDCapture`` and this will ``CloseHandle`` the
handles used by Python to write to the console. Though there is still some
weirdness and the console handle seems to only be closed randomly and not
on the first call to ``CloseHandle``, or maybe it gets reopened with the
same handle value when we suspend capturing.
The workaround in this case will reopen stdio with a different fd which
also means a different handle by replicating the logic in
"Py_lifecycle.c:initstdio/create_stdio".
See https://github.com/pytest-dev/py/issues/103
"""
if not sys.platform.startswith('win32') or sys.version_info[:2] < (3, 6):
return
buffered = hasattr(sys.stdout.buffer, 'raw')
raw_stdout = sys.stdout.buffer.raw if buffered else sys.stdout.buffer
if not isinstance(raw_stdout, io._WindowsConsoleIO):
return
def _reopen_stdio(f, mode):
if not buffered and mode[0] == 'w':
buffering = 0
else:
buffering = -1
return io.TextIOWrapper(
open(os.dup(f.fileno()), mode, buffering),
f.encoding,
f.errors,
f.newlines,
f.line_buffering)
sys.__stdin__ = sys.stdin = _reopen_stdio(sys.stdin, 'rb')
sys.__stdout__ = sys.stdout = _reopen_stdio(sys.stdout, 'wb')
sys.__stderr__ = sys.stderr = _reopen_stdio(sys.stderr, 'wb')