doctest.py

""" discover and run doctests in modules and test files."""
from __future__ import absolute_import, division, print_function

import traceback
import sys
import platform

import pytest
from _pytest._code.code import ExceptionInfo, ReprFileLocation, TerminalRepr
from _pytest.fixtures import FixtureRequest


DOCTEST_REPORT_CHOICE_NONE = "none"
DOCTEST_REPORT_CHOICE_CDIFF = "cdiff"
DOCTEST_REPORT_CHOICE_NDIFF = "ndiff"
DOCTEST_REPORT_CHOICE_UDIFF = "udiff"
DOCTEST_REPORT_CHOICE_ONLY_FIRST_FAILURE = "only_first_failure"

DOCTEST_REPORT_CHOICES = (
    DOCTEST_REPORT_CHOICE_NONE,
    DOCTEST_REPORT_CHOICE_CDIFF,
    DOCTEST_REPORT_CHOICE_NDIFF,
    DOCTEST_REPORT_CHOICE_UDIFF,
    DOCTEST_REPORT_CHOICE_ONLY_FIRST_FAILURE,
)

# Lazy definition of runner class
RUNNER_CLASS = None


def pytest_addoption(parser):
    parser.addini(
        "doctest_optionflags",
        "option flags for doctests",
        type="args",
        default=["ELLIPSIS"],
    )
    parser.addini(
        "doctest_encoding", "encoding used for doctest files", default="utf-8"
    )
    group = parser.getgroup("collect")
    group.addoption(
        "--doctest-modules",
        action="store_true",
        default=False,
        help="run doctests in all .py modules",
        dest="doctestmodules",
    )
    group.addoption(
        "--doctest-report",
        type=str.lower,
        default="udiff",
        help="choose another output format for diffs on doctest failure",
        choices=DOCTEST_REPORT_CHOICES,
        dest="doctestreport",
    )
    group.addoption(
        "--doctest-glob",
        action="append",
        default=[],
        metavar="pat",
        help="doctests file matching pattern, default: test*.txt",
        dest="doctestglob",
    )
    group.addoption(
        "--doctest-ignore-import-errors",
        action="store_true",
        default=False,
        help="ignore doctest ImportErrors",
        dest="doctest_ignore_import_errors",
    )
    group.addoption(
        "--doctest-continue-on-failure",
        action="store_true",
        default=False,
        help="for a given doctest, continue to run after the first failure",
        dest="doctest_continue_on_failure",
    )


def pytest_collect_file(path, parent):
    config = parent.config
    if path.ext == ".py":
        if config.option.doctestmodules and not _is_setup_py(config, path, parent):
            return DoctestModule(path, parent)
    elif _is_doctest(config, path, parent):
        return DoctestTextfile(path, parent)


def _is_setup_py(config, path, parent):
    if path.basename != "setup.py":
        return False
    contents = path.read()
    return "setuptools" in contents or "distutils" in contents


def _is_doctest(config, path, parent):
    if path.ext in (".txt", ".rst") and parent.session.isinitpath(path):
        return True
    globs = config.getoption("doctestglob") or ["test*.txt"]
    for glob in globs:
        if path.check(fnmatch=glob):
            return True
    return False


class ReprFailDoctest(TerminalRepr):
    def __init__(self, reprlocation_lines):
        # List of (reprlocation, lines) tuples
        self.reprlocation_lines = reprlocation_lines

    def toterminal(self, tw):
        for reprlocation, lines in self.reprlocation_lines:
            for line in lines:
                tw.line(line)
            reprlocation.toterminal(tw)


class MultipleDoctestFailures(Exception):
    def __init__(self, failures):
        super(MultipleDoctestFailures, self).__init__()
        self.failures = failures


def _init_runner_class():
    import doctest

    class PytestDoctestRunner(doctest.DebugRunner):
        """
        Runner to collect failures.  Note that the out variable in this case is
        a list instead of a stdout-like object
        """

        def __init__(
            self, checker=None, verbose=None, optionflags=0, continue_on_failure=True
        ):
            doctest.DebugRunner.__init__(
                self, checker=checker, verbose=verbose, optionflags=optionflags
            )
            self.continue_on_failure = continue_on_failure

        def report_failure(self, out, test, example, got):
            failure = doctest.DocTestFailure(test, example, got)
            if self.continue_on_failure:
                out.append(failure)
            else:
                raise failure

        def report_unexpected_exception(self, out, test, example, exc_info):
            failure = doctest.UnexpectedException(test, example, exc_info)
            if self.continue_on_failure:
                out.append(failure)
            else:
                raise failure

    return PytestDoctestRunner


def _get_runner(checker=None, verbose=None, optionflags=0, continue_on_failure=True):
    # We need this in order to do a lazy import on doctest
    global RUNNER_CLASS
    if RUNNER_CLASS is None:
        RUNNER_CLASS = _init_runner_class()
    return RUNNER_CLASS(
        checker=checker,
        verbose=verbose,
        optionflags=optionflags,
        continue_on_failure=continue_on_failure,
    )


class DoctestItem(pytest.Item):
    def __init__(self, name, parent, runner=None, dtest=None):
        super(DoctestItem, self).__init__(name, parent)
        self.runner = runner
        self.dtest = dtest
        self.obj = None
        self.fixture_request = None

    def setup(self):
        if self.dtest is not None:
            self.fixture_request = _setup_fixtures(self)
            globs = dict(getfixture=self.fixture_request.getfixturevalue)
            for name, value in self.fixture_request.getfixturevalue(
                "doctest_namespace"
            ).items():
                globs[name] = value
            self.dtest.globs.update(globs)

    def runtest(self):
        _check_all_skipped(self.dtest)
        self._disable_output_capturing_for_darwin()
        failures = []
        self.runner.run(self.dtest, out=failures)
        if failures:
            raise MultipleDoctestFailures(failures)

    def _disable_output_capturing_for_darwin(self):
        """
        Disable output capturing. Otherwise, stdout is lost to doctest (#985)
        """
        if platform.system() != "Darwin":
            return
        capman = self.config.pluginmanager.getplugin("capturemanager")
        if capman:
            capman.suspend_global_capture(in_=True)
            out, err = capman.read_global_capture()
            sys.stdout.write(out)
            sys.stderr.write(err)

    def repr_failure(self, excinfo):
        import doctest

        failures = None
        if excinfo.errisinstance((doctest.DocTestFailure, doctest.UnexpectedException)):
            failures = [excinfo.value]
        elif excinfo.errisinstance(MultipleDoctestFailures):
            failures = excinfo.value.failures

        if failures is not None:
            reprlocation_lines = []
            for failure in failures:
                example = failure.example
                test = failure.test
                filename = test.filename
                if test.lineno is None:
                    lineno = None
                else:
                    lineno = test.lineno + example.lineno + 1
                message = type(failure).__name__
                reprlocation = ReprFileLocation(filename, lineno, message)
                checker = _get_checker()
                report_choice = _get_report_choice(
                    self.config.getoption("doctestreport")
                )
                if lineno is not None:
                    lines = failure.test.docstring.splitlines(False)
                    # add line numbers to the left of the error message
                    lines = [
                        "%03d %s" % (i + test.lineno + 1, x)
                        for (i, x) in enumerate(lines)
                    ]
                    # trim docstring error lines to 10
                    lines = lines[max(example.lineno - 9, 0) : example.lineno + 1]
                else:
                    lines = [
                        "EXAMPLE LOCATION UNKNOWN, not showing all tests of that example"
                    ]
                    indent = ">>>"
                    for line in example.source.splitlines():
                        lines.append("??? %s %s" % (indent, line))
                        indent = "..."
                if isinstance(failure, doctest.DocTestFailure):
                    lines += checker.output_difference(
                        example, failure.got, report_choice
                    ).split("\n")
                else:
                    inner_excinfo = ExceptionInfo(failure.exc_info)
                    lines += ["UNEXPECTED EXCEPTION: %s" % repr(inner_excinfo.value)]
                    lines += traceback.format_exception(*failure.exc_info)
                reprlocation_lines.append((reprlocation, lines))
            return ReprFailDoctest(reprlocation_lines)
        else:
            return super(DoctestItem, self).repr_failure(excinfo)

    def reportinfo(self):
        return self.fspath, self.dtest.lineno, "[doctest] %s" % self.name


def _get_flag_lookup():
    import doctest

    return dict(
        DONT_ACCEPT_TRUE_FOR_1=doctest.DONT_ACCEPT_TRUE_FOR_1,
        DONT_ACCEPT_BLANKLINE=doctest.DONT_ACCEPT_BLANKLINE,
        NORMALIZE_WHITESPACE=doctest.NORMALIZE_WHITESPACE,
        ELLIPSIS=doctest.ELLIPSIS,
        IGNORE_EXCEPTION_DETAIL=doctest.IGNORE_EXCEPTION_DETAIL,
        COMPARISON_FLAGS=doctest.COMPARISON_FLAGS,
        ALLOW_UNICODE=_get_allow_unicode_flag(),
        ALLOW_BYTES=_get_allow_bytes_flag(),
    )


def get_optionflags(parent):
    optionflags_str = parent.config.getini("doctest_optionflags")
    flag_lookup_table = _get_flag_lookup()
    flag_acc = 0
    for flag in optionflags_str:
        flag_acc |= flag_lookup_table[flag]
    return flag_acc


def _get_continue_on_failure(config):
    continue_on_failure = config.getvalue("doctest_continue_on_failure")
    if continue_on_failure:
        # We need to turn off this if we use pdb since we should stop at
        # the first failure
        if config.getvalue("usepdb"):
            continue_on_failure = False
    return continue_on_failure


class DoctestTextfile(pytest.Module):
    obj = None

    def collect(self):
        import doctest

        # inspired by doctest.testfile; ideally we would use it directly,
        # but it doesn't support passing a custom checker
        encoding = self.config.getini("doctest_encoding")
        text = self.fspath.read_text(encoding)
        filename = str(self.fspath)
        name = self.fspath.basename
        globs = {"__name__": "__main__"}

        optionflags = get_optionflags(self)

        runner = _get_runner(
            verbose=0,
            optionflags=optionflags,
            checker=_get_checker(),
            continue_on_failure=_get_continue_on_failure(self.config),
        )
        _fix_spoof_python2(runner, encoding)

        parser = doctest.DocTestParser()
        test = parser.get_doctest(text, globs, name, filename, 0)
        if test.examples:
            yield DoctestItem(test.name, self, runner, test)


def _check_all_skipped(test):
    """raises pytest.skip() if all examples in the given DocTest have the SKIP
    option set.
    """
    import doctest

    all_skipped = all(x.options.get(doctest.SKIP, False) for x in test.examples)
    if all_skipped:
        pytest.skip("all tests skipped by +SKIP option")


class DoctestModule(pytest.Module):
    def collect(self):
        import doctest

        if self.fspath.basename == "conftest.py":
            module = self.config.pluginmanager._importconftest(self.fspath)
        else:
            try:
                module = self.fspath.pyimport()
            except ImportError:
                if self.config.getvalue("doctest_ignore_import_errors"):
                    pytest.skip("unable to import module %r" % self.fspath)
                else:
                    raise
        # uses internal doctest module parsing mechanism
        finder = doctest.DocTestFinder()
        optionflags = get_optionflags(self)
        runner = _get_runner(
            verbose=0,
            optionflags=optionflags,
            checker=_get_checker(),
            continue_on_failure=_get_continue_on_failure(self.config),
        )

        for test in finder.find(module, module.__name__):
            if test.examples:  # skip empty doctests
                yield DoctestItem(test.name, self, runner, test)


def _setup_fixtures(doctest_item):
    """
    Used by DoctestTextfile and DoctestItem to setup fixture information.
    """

    def func():
        pass

    doctest_item.funcargs = {}
    fm = doctest_item.session._fixturemanager
    doctest_item._fixtureinfo = fm.getfixtureinfo(
        node=doctest_item, func=func, cls=None, funcargs=False
    )
    fixture_request = FixtureRequest(doctest_item)
    fixture_request._fillfixtures()
    return fixture_request


def _get_checker():
    """
    Returns a doctest.OutputChecker subclass that takes in account the
    ALLOW_UNICODE option to ignore u'' prefixes in strings and ALLOW_BYTES
    to strip b'' prefixes.
    Useful when the same doctest should run in Python 2 and Python 3.

    An inner class is used to avoid importing "doctest" at the module
    level.
    """
    if hasattr(_get_checker, "LiteralsOutputChecker"):
        return _get_checker.LiteralsOutputChecker()

    import doctest
    import re

    class LiteralsOutputChecker(doctest.OutputChecker):
        """
        Copied from doctest_nose_plugin.py from the nltk project:
            https://github.com/nltk/nltk

        Further extended to also support byte literals.
        """

        _unicode_literal_re = re.compile(r"(\W|^)[uU]([rR]?[\'\"])", re.UNICODE)
        _bytes_literal_re = re.compile(r"(\W|^)[bB]([rR]?[\'\"])", re.UNICODE)

        def check_output(self, want, got, optionflags):
            res = doctest.OutputChecker.check_output(self, want, got, optionflags)
            if res:
                return True

            allow_unicode = optionflags & _get_allow_unicode_flag()
            allow_bytes = optionflags & _get_allow_bytes_flag()
            if not allow_unicode and not allow_bytes:
                return False

            else:  # pragma: no cover

                def remove_prefixes(regex, txt):
                    return re.sub(regex, r"\1\2", txt)

                if allow_unicode:
                    want = remove_prefixes(self._unicode_literal_re, want)
                    got = remove_prefixes(self._unicode_literal_re, got)
                if allow_bytes:
                    want = remove_prefixes(self._bytes_literal_re, want)
                    got = remove_prefixes(self._bytes_literal_re, got)
                res = doctest.OutputChecker.check_output(self, want, got, optionflags)
                return res

    _get_checker.LiteralsOutputChecker = LiteralsOutputChecker
    return _get_checker.LiteralsOutputChecker()


def _get_allow_unicode_flag():
    """
    Registers and returns the ALLOW_UNICODE flag.
    """
    import doctest

    return doctest.register_optionflag("ALLOW_UNICODE")


def _get_allow_bytes_flag():
    """
    Registers and returns the ALLOW_BYTES flag.
    """
    import doctest

    return doctest.register_optionflag("ALLOW_BYTES")


def _get_report_choice(key):
    """
    This function returns the actual `doctest` module flag value, we want to do it as late as possible to avoid
    importing `doctest` and all its dependencies when parsing options, as it adds overhead and breaks tests.
    """
    import doctest

    return {
        DOCTEST_REPORT_CHOICE_UDIFF: doctest.REPORT_UDIFF,
        DOCTEST_REPORT_CHOICE_CDIFF: doctest.REPORT_CDIFF,
        DOCTEST_REPORT_CHOICE_NDIFF: doctest.REPORT_NDIFF,
        DOCTEST_REPORT_CHOICE_ONLY_FIRST_FAILURE: doctest.REPORT_ONLY_FIRST_FAILURE,
        DOCTEST_REPORT_CHOICE_NONE: 0,
    }[key]


def _fix_spoof_python2(runner, encoding):
    """
    Installs a "SpoofOut" into the given DebugRunner so it properly deals with unicode output. This
    should patch only doctests for text files because they don't have a way to declare their
    encoding. Doctests in docstrings from Python modules don't have the same problem given that
    Python already decoded the strings.

    This fixes the problem related in issue #2434.
    """
    from _pytest.compat import _PY2

    if not _PY2:
        return

    from doctest import _SpoofOut

    class UnicodeSpoof(_SpoofOut):
        def getvalue(self):
            result = _SpoofOut.getvalue(self)
            if encoding and isinstance(result, bytes):
                result = result.decode(encoding)
            return result

    runner._fakeout = UnicodeSpoof()


@pytest.fixture(scope="session")
def doctest_namespace():
    """
    Fixture that returns a :py:class:`dict` that will be injected into the namespace of doctests.
    """
    return dict()