base.py

#!/usr/bin/python3

# This file is part of libmodulemd
# Copyright (C) 2018 Red Hat, Inc.
#
# Fedora-License-Identifier: MIT
# SPDX-2.0-License-Identifier: MIT
# SPDX-3.0-License-Identifier: MIT
#
# This program is free software.
# For more information on the license, see COPYING.
# For more information on free software, see
# <https://www.gnu.org/philosophy/free-sw.en.html>.

from contextlib import contextmanager
import signal
import os
import unittest


class TestBase(unittest.TestCase):
    def __init__(self, *args, **kwargs):
        super(TestBase, self).__init__(*args, **kwargs)
        self._caught_signal = False

    @property
    def source_root(self):
        return os.getenv("MESON_SOURCE_ROOT")

    @property
    def test_data_path(self):
        return os.getenv("TEST_DATA_PATH")

    def _catch_signal(self, *sigargs):
        if self._caught_signal:
            raise AssertionError("Multiple signals were caught")
        self._caught_signal = True

    @contextmanager
    def expect_signal(
        self, expected_signal=signal.SIGTRAP, only_on_fatal_warnings=False
    ):
        expect_signal = (not only_on_fatal_warnings) or self.warnings_fatal

        self._caught_signal = False

        saved_signal = signal.signal(expected_signal, self._catch_signal)
        yield None
        signal.signal(expected_signal, saved_signal)
        if not self._caught_signal and expect_signal:
            raise AssertionError("No signal got caught")
        elif self._caught_signal and not expect_signal:
            raise AssertionError("Signal caught in non-warning state")

    def assertProcessFailure(self, callable, *args):
        """Calls the callable in a subprocess and checks whether the process was
        killed with a signal depending on Glib warning fatality."""
        pid = os.fork()
        if pid == 0:
            callable(*args)
            os._exit(0)
        _, status = os.waitpid(pid, 0)
        if self.warnings_fatal:
            if not os.WIFSIGNALED(status):
                raise AssertionError("Child process was not aborted")
        else:
            if os.WIFSIGNALED(status):
                raise AssertionError("Child process was unexpectedly aborted")

    def assertTypeExceptionOrProcessFailure(self, callable, *args):
        """Calls the callable in a subprocess and checks that the process
        raised a TypeError exception, or was killed depending on Glib warning
        fatality.

        Since pygobject-3.55.0 setting a G_PARAM_CONSTRUCT_ONLY property
        raises a Python exception. Old pygobject continues down to Glib
        which kills the process if Glib warnings a fatal, otherwise Glib
        warning is printed and the code continues.
        """
        pid = os.fork()
        if pid == 0:
            try:
                callable(*args)
            except TypeError:
                os._exit(1)
            os._exit(0)
        _, status = os.waitpid(pid, 0)
        if os.WIFEXITED(status) and os.WEXITSTATUS(status) == 1:
            return
        if self.warnings_fatal:
            if not os.WIFSIGNALED(status):
                raise AssertionError(
                    "Child process did not raise TypeError "
                    "exception or was not aborted"
                )
        else:
            if os.WIFSIGNALED(status):
                raise AssertionError("Child process was unexpectedly aborted")

    @property
    def warnings_fatal(self):
        gdebug = os.getenv("G_DEBUG", "").split(",")
        return "fatal-warnings" in gdebug

    def assertRaisesRegex(self, *args, **kwargs):
        """Asserts that the message in a raised exception matches a regex.

        Args:
            The same as unittest.TestCase.assertRaisesRegex().
        """
        try:
            return super(TestBase, self).assertRaisesRegex(*args, **kwargs)
        except AttributeError:
            return self.assertRaisesRegexp(*args, **kwargs)

    def assertRaisesRegexOrDies(self, callable, *args, **kwargs):
        """Checks that the callable terminates a process if Glib warnings are
        fatal. Otherwise, that the callable raised a given exception type with
        the given value matching a regular expression."""
        if self.warnings_fatal:
            self.assertProcessFailure(callable)
        else:
            with self.assertRaisesRegex(*args, **kwargs):
                callable()