diff options
Diffstat (limited to 'python/pytest/_pytest/capture.py')
| -rw-r--r-- | python/pytest/_pytest/capture.py | 472 |
1 files changed, 472 insertions, 0 deletions
diff --git a/python/pytest/_pytest/capture.py b/python/pytest/_pytest/capture.py new file mode 100644 index 000000000..3895a714a --- /dev/null +++ b/python/pytest/_pytest/capture.py @@ -0,0 +1,472 @@ +""" +per-test stdout/stderr capturing mechanism. + +""" +from __future__ import with_statement + +import sys +import os +from tempfile import TemporaryFile + +import py +import pytest + +from py.io import TextIO +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): + _readline_workaround() + ns = early_config.known_args_namespace + 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): + out, err = self.suspendcapture() + 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): + """enables capturing of writes to sys.stdout/sys.stderr and makes + captured output available via ``capsys.readouterr()`` method calls + which return a ``(out, err)`` tuple. + """ + if "capfd" in request._funcargs: + raise request.raiseerror(error_capsysfderror) + request.node._capfuncarg = c = CaptureFixture(SysCapture) + return c + +@pytest.fixture +def capfd(request): + """enables capturing of writes to file descriptors 1 and 2 and makes + captured output available via ``capfd.readouterr()`` method calls + which return a ``(out, err)`` tuple. + """ + if "capsys" in request._funcargs: + request.raiseerror(error_capsysfderror) + if not hasattr(os, 'dup'): + pytest.skip("capfd funcarg needs os.dup") + request.node._capfuncarg = c = CaptureFixture(FDCapture) + return c + + +class CaptureFixture: + def __init__(self, captureclass): + self.captureclass = captureclass + + 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 + + +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) + + 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 = TextIO() + 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 ValueError("redirected Stdin is pseudofile, has no fileno()") + + def isatty(self): + return False + + def close(self): + 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 py.test 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 |