manyi/venv/Lib/site-packages/psutil/tests/test_linux.py

#!/usr/bin/env python3

# Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Linux specific tests."""

from __future__ import division
import collections
import contextlib
import errno
import glob
import io
import os
import re
import shutil
import socket
import struct
import textwrap
import time
import warnings

import psutil
from psutil import LINUX
from psutil._compat import basestring
from psutil._compat import FileNotFoundError
from psutil._compat import PY3
from psutil._compat import u
from psutil.tests import call_until
from psutil.tests import GLOBAL_TIMEOUT
from psutil.tests import HAS_BATTERY
from psutil.tests import HAS_CPU_FREQ
from psutil.tests import HAS_GETLOADAVG
from psutil.tests import HAS_RLIMIT
from psutil.tests import mock
from psutil.tests import PsutilTestCase
from psutil.tests import PYPY
from psutil.tests import reload_module
from psutil.tests import retry_on_failure
from psutil.tests import safe_rmpath
from psutil.tests import sh
from psutil.tests import skip_on_not_implemented
from psutil.tests import ThreadTask
from psutil.tests import TOLERANCE_DISK_USAGE
from psutil.tests import TOLERANCE_SYS_MEM
from psutil.tests import TRAVIS
from psutil.tests import unittest
from psutil.tests import which


HERE = os.path.abspath(os.path.dirname(__file__))
SIOCGIFADDR = 0x8915
SIOCGIFCONF = 0x8912
SIOCGIFHWADDR = 0x8927
SIOCGIFNETMASK = 0x891b
SIOCGIFBRDADDR = 0x8919
if LINUX:
    SECTOR_SIZE = 512
EMPTY_TEMPERATURES = not glob.glob('/sys/class/hwmon/hwmon*')

# =====================================================================
# --- utils
# =====================================================================


def get_ipv4_address(ifname):
    import fcntl
    ifname = ifname[:15]
    if PY3:
        ifname = bytes(ifname, 'ascii')
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    with contextlib.closing(s):
        return socket.inet_ntoa(
            fcntl.ioctl(s.fileno(),
                        SIOCGIFADDR,
                        struct.pack('256s', ifname))[20:24])


def get_ipv4_netmask(ifname):
    import fcntl
    ifname = ifname[:15]
    if PY3:
        ifname = bytes(ifname, 'ascii')
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    with contextlib.closing(s):
        return socket.inet_ntoa(
            fcntl.ioctl(s.fileno(),
                        SIOCGIFNETMASK,
                        struct.pack('256s', ifname))[20:24])


def get_ipv4_broadcast(ifname):
    import fcntl
    ifname = ifname[:15]
    if PY3:
        ifname = bytes(ifname, 'ascii')
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    with contextlib.closing(s):
        return socket.inet_ntoa(
            fcntl.ioctl(s.fileno(),
                        SIOCGIFBRDADDR,
                        struct.pack('256s', ifname))[20:24])


def get_ipv6_address(ifname):
    with open("/proc/net/if_inet6", 'rt') as f:
        for line in f.readlines():
            fields = line.split()
            if fields[-1] == ifname:
                break
        else:
            raise ValueError("could not find interface %r" % ifname)
    unformatted = fields[0]
    groups = []
    for i in range(0, len(unformatted), 4):
        groups.append(unformatted[i:i + 4])
    formatted = ":".join(groups)
    packed = socket.inet_pton(socket.AF_INET6, formatted)
    return socket.inet_ntop(socket.AF_INET6, packed)


def get_mac_address(ifname):
    import fcntl
    ifname = ifname[:15]
    if PY3:
        ifname = bytes(ifname, 'ascii')
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    with contextlib.closing(s):
        info = fcntl.ioctl(
            s.fileno(), SIOCGIFHWADDR, struct.pack('256s', ifname))
        if PY3:
            def ord(x):
                return x
        else:
            import __builtin__
            ord = __builtin__.ord
        return ''.join(['%02x:' % ord(char) for char in info[18:24]])[:-1]


def free_swap():
    """Parse 'free' cmd and return swap memory's s total, used and free
    values.
    """
    out = sh('free -b', env={"LANG": "C.UTF-8"})
    lines = out.split('\n')
    for line in lines:
        if line.startswith('Swap'):
            _, total, used, free = line.split()
            nt = collections.namedtuple('free', 'total used free')
            return nt(int(total), int(used), int(free))
    raise ValueError(
        "can't find 'Swap' in 'free' output:\n%s" % '\n'.join(lines))


def free_physmem():
    """Parse 'free' cmd and return physical memory's total, used
    and free values.
    """
    # Note: free can have 2 different formats, invalidating 'shared'
    # and 'cached' memory which may have different positions so we
    # do not return them.
    # https://github.com/giampaolo/psutil/issues/538#issuecomment-57059946
    out = sh('free -b', env={"LANG": "C.UTF-8"})
    lines = out.split('\n')
    for line in lines:
        if line.startswith('Mem'):
            total, used, free, shared = \
                [int(x) for x in line.split()[1:5]]
            nt = collections.namedtuple(
                'free', 'total used free shared output')
            return nt(total, used, free, shared, out)
    raise ValueError(
        "can't find 'Mem' in 'free' output:\n%s" % '\n'.join(lines))


def vmstat(stat):
    out = sh("vmstat -s", env={"LANG": "C.UTF-8"})
    for line in out.split("\n"):
        line = line.strip()
        if stat in line:
            return int(line.split(' ')[0])
    raise ValueError("can't find %r in 'vmstat' output" % stat)


def get_free_version_info():
    out = sh("free -V").strip()
    if 'UNKNOWN' in out:
        raise unittest.SkipTest("can't determine free version")
    return tuple(map(int, out.split()[-1].split('.')))


@contextlib.contextmanager
def mock_open_content(for_path, content):
    """Mock open() builtin and forces it to return a certain `content`
    on read() if the path being opened matches `for_path`.
    """
    def open_mock(name, *args, **kwargs):
        if name == for_path:
            if PY3:
                if isinstance(content, basestring):
                    return io.StringIO(content)
                else:
                    return io.BytesIO(content)
            else:
                return io.BytesIO(content)
        else:
            return orig_open(name, *args, **kwargs)

    orig_open = open
    patch_point = 'builtins.open' if PY3 else '__builtin__.open'
    with mock.patch(patch_point, create=True, side_effect=open_mock) as m:
        yield m


@contextlib.contextmanager
def mock_open_exception(for_path, exc):
    """Mock open() builtin and raises `exc` if the path being opened
    matches `for_path`.
    """
    def open_mock(name, *args, **kwargs):
        if name == for_path:
            raise exc
        else:
            return orig_open(name, *args, **kwargs)

    orig_open = open
    patch_point = 'builtins.open' if PY3 else '__builtin__.open'
    with mock.patch(patch_point, create=True, side_effect=open_mock) as m:
        yield m


# =====================================================================
# --- system virtual memory
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemVirtualMemory(PsutilTestCase):

    def test_total(self):
        # free_value = free_physmem().total
        # psutil_value = psutil.virtual_memory().total
        # self.assertEqual(free_value, psutil_value)
        vmstat_value = vmstat('total memory') * 1024
        psutil_value = psutil.virtual_memory().total
        self.assertAlmostEqual(vmstat_value, psutil_value)

    @retry_on_failure()
    def test_used(self):
        # Older versions of procps used slab memory to calculate used memory.
        # This got changed in:
        # https://gitlab.com/procps-ng/procps/commit/
        #     05d751c4f076a2f0118b914c5e51cfbb4762ad8e
        if get_free_version_info() < (3, 3, 12):
            raise self.skipTest("old free version")
        free = free_physmem()
        free_value = free.used
        psutil_value = psutil.virtual_memory().used
        self.assertAlmostEqual(
            free_value, psutil_value, delta=TOLERANCE_SYS_MEM,
            msg='%s %s \n%s' % (free_value, psutil_value, free.output))

    @unittest.skipIf(TRAVIS, "unreliable on TRAVIS")
    @retry_on_failure()
    def test_free(self):
        vmstat_value = vmstat('free memory') * 1024
        psutil_value = psutil.virtual_memory().free
        self.assertAlmostEqual(
            vmstat_value, psutil_value, delta=TOLERANCE_SYS_MEM)

    @retry_on_failure()
    def test_buffers(self):
        vmstat_value = vmstat('buffer memory') * 1024
        psutil_value = psutil.virtual_memory().buffers
        self.assertAlmostEqual(
            vmstat_value, psutil_value, delta=TOLERANCE_SYS_MEM)

    # https://travis-ci.org/giampaolo/psutil/jobs/226719664
    @unittest.skipIf(TRAVIS, "unreliable on TRAVIS")
    @retry_on_failure()
    def test_active(self):
        vmstat_value = vmstat('active memory') * 1024
        psutil_value = psutil.virtual_memory().active
        self.assertAlmostEqual(
            vmstat_value, psutil_value, delta=TOLERANCE_SYS_MEM)

    # https://travis-ci.org/giampaolo/psutil/jobs/227242952
    @unittest.skipIf(TRAVIS, "unreliable on TRAVIS")
    @retry_on_failure()
    def test_inactive(self):
        vmstat_value = vmstat('inactive memory') * 1024
        psutil_value = psutil.virtual_memory().inactive
        self.assertAlmostEqual(
            vmstat_value, psutil_value, delta=TOLERANCE_SYS_MEM)

    @retry_on_failure()
    def test_shared(self):
        free = free_physmem()
        free_value = free.shared
        if free_value == 0:
            raise unittest.SkipTest("free does not support 'shared' column")
        psutil_value = psutil.virtual_memory().shared
        self.assertAlmostEqual(
            free_value, psutil_value, delta=TOLERANCE_SYS_MEM,
            msg='%s %s \n%s' % (free_value, psutil_value, free.output))

    @retry_on_failure()
    def test_available(self):
        # "free" output format has changed at some point:
        # https://github.com/giampaolo/psutil/issues/538#issuecomment-147192098
        out = sh("free -b")
        lines = out.split('\n')
        if 'available' not in lines[0]:
            raise unittest.SkipTest("free does not support 'available' column")
        else:
            free_value = int(lines[1].split()[-1])
            psutil_value = psutil.virtual_memory().available
            self.assertAlmostEqual(
                free_value, psutil_value, delta=TOLERANCE_SYS_MEM,
                msg='%s %s \n%s' % (free_value, psutil_value, out))

    def test_warnings_on_misses(self):
        # Emulate a case where /proc/meminfo provides few info.
        # psutil is supposed to set the missing fields to 0 and
        # raise a warning.
        with mock_open_content(
            '/proc/meminfo',
            textwrap.dedent("""\
                Active(anon):    6145416 kB
                Active(file):    2950064 kB
                Inactive(anon):   574764 kB
                Inactive(file):  1567648 kB
                MemAvailable:         -1 kB
                MemFree:         2057400 kB
                MemTotal:       16325648 kB
                SReclaimable:     346648 kB
                """).encode()) as m:
            with warnings.catch_warnings(record=True) as ws:
                warnings.simplefilter("always")
                ret = psutil.virtual_memory()
                assert m.called
                self.assertEqual(len(ws), 1)
                w = ws[0]
                assert w.filename.endswith('psutil/_pslinux.py')
                self.assertIn(
                    "memory stats couldn't be determined", str(w.message))
                self.assertIn("cached", str(w.message))
                self.assertIn("shared", str(w.message))
                self.assertIn("active", str(w.message))
                self.assertIn("inactive", str(w.message))
                self.assertIn("buffers", str(w.message))
                self.assertIn("available", str(w.message))
                self.assertEqual(ret.cached, 0)
                self.assertEqual(ret.active, 0)
                self.assertEqual(ret.inactive, 0)
                self.assertEqual(ret.shared, 0)
                self.assertEqual(ret.buffers, 0)
                self.assertEqual(ret.available, 0)
                self.assertEqual(ret.slab, 0)

    @retry_on_failure()
    def test_avail_old_percent(self):
        # Make sure that our calculation of avail mem for old kernels
        # is off by max 15%.
        from psutil._pslinux import calculate_avail_vmem
        from psutil._pslinux import open_binary

        mems = {}
        with open_binary('/proc/meminfo') as f:
            for line in f:
                fields = line.split()
                mems[fields[0]] = int(fields[1]) * 1024

        a = calculate_avail_vmem(mems)
        if b'MemAvailable:' in mems:
            b = mems[b'MemAvailable:']
            diff_percent = abs(a - b) / a * 100
            self.assertLess(diff_percent, 15)

    def test_avail_old_comes_from_kernel(self):
        # Make sure "MemAvailable:" coluimn is used instead of relying
        # on our internal algorithm to calculate avail mem.
        with mock_open_content(
            '/proc/meminfo',
            textwrap.dedent("""\
                Active:          9444728 kB
                Active(anon):    6145416 kB
                Active(file):    2950064 kB
                Buffers:          287952 kB
                Cached:          4818144 kB
                Inactive(file):  1578132 kB
                Inactive(anon):   574764 kB
                Inactive(file):  1567648 kB
                MemAvailable:    6574984 kB
                MemFree:         2057400 kB
                MemTotal:       16325648 kB
                Shmem:            577588 kB
                SReclaimable:     346648 kB
                """).encode()) as m:
            with warnings.catch_warnings(record=True) as ws:
                ret = psutil.virtual_memory()
            assert m.called
            self.assertEqual(ret.available, 6574984 * 1024)
            w = ws[0]
            self.assertIn(
                "inactive memory stats couldn't be determined", str(w.message))

    def test_avail_old_missing_fields(self):
        # Remove Active(file), Inactive(file) and SReclaimable
        # from /proc/meminfo and make sure the fallback is used
        # (free + cached),
        with mock_open_content(
            "/proc/meminfo",
            textwrap.dedent("""\
                    Active:          9444728 kB
                    Active(anon):    6145416 kB
                    Buffers:          287952 kB
                    Cached:          4818144 kB
                    Inactive(file):  1578132 kB
                    Inactive(anon):   574764 kB
                    MemFree:         2057400 kB
                    MemTotal:       16325648 kB
                    Shmem:            577588 kB
                    """).encode()) as m:
            with warnings.catch_warnings(record=True) as ws:
                ret = psutil.virtual_memory()
            assert m.called
            self.assertEqual(ret.available, 2057400 * 1024 + 4818144 * 1024)
            w = ws[0]
            self.assertIn(
                "inactive memory stats couldn't be determined", str(w.message))

    def test_avail_old_missing_zoneinfo(self):
        # Remove /proc/zoneinfo file. Make sure fallback is used
        # (free + cached).
        with mock_open_content(
                "/proc/meminfo",
                textwrap.dedent("""\
                    Active:          9444728 kB
                    Active(anon):    6145416 kB
                    Active(file):    2950064 kB
                    Buffers:          287952 kB
                    Cached:          4818144 kB
                    Inactive(file):  1578132 kB
                    Inactive(anon):   574764 kB
                    Inactive(file):  1567648 kB
                    MemFree:         2057400 kB
                    MemTotal:       16325648 kB
                    Shmem:            577588 kB
                    SReclaimable:     346648 kB
                    """).encode()):
            with mock_open_exception(
                    "/proc/zoneinfo",
                    IOError(errno.ENOENT, 'no such file or directory')):
                with warnings.catch_warnings(record=True) as ws:
                    ret = psutil.virtual_memory()
                    self.assertEqual(
                        ret.available, 2057400 * 1024 + 4818144 * 1024)
                    w = ws[0]
                    self.assertIn(
                        "inactive memory stats couldn't be determined",
                        str(w.message))

    def test_virtual_memory_mocked(self):
        # Emulate /proc/meminfo because neither vmstat nor free return slab.
        def open_mock(name, *args, **kwargs):
            if name == '/proc/meminfo':
                return io.BytesIO(textwrap.dedent("""\
                    MemTotal:              100 kB
                    MemFree:               2 kB
                    MemAvailable:          3 kB
                    Buffers:               4 kB
                    Cached:                5 kB
                    SwapCached:            6 kB
                    Active:                7 kB
                    Inactive:              8 kB
                    Active(anon):          9 kB
                    Inactive(anon):        10 kB
                    Active(file):          11 kB
                    Inactive(file):        12 kB
                    Unevictable:           13 kB
                    Mlocked:               14 kB
                    SwapTotal:             15 kB
                    SwapFree:              16 kB
                    Dirty:                 17 kB
                    Writeback:             18 kB
                    AnonPages:             19 kB
                    Mapped:                20 kB
                    Shmem:                 21 kB
                    Slab:                  22 kB
                    SReclaimable:          23 kB
                    SUnreclaim:            24 kB
                    KernelStack:           25 kB
                    PageTables:            26 kB
                    NFS_Unstable:          27 kB
                    Bounce:                28 kB
                    WritebackTmp:          29 kB
                    CommitLimit:           30 kB
                    Committed_AS:          31 kB
                    VmallocTotal:          32 kB
                    VmallocUsed:           33 kB
                    VmallocChunk:          34 kB
                    HardwareCorrupted:     35 kB
                    AnonHugePages:         36 kB
                    ShmemHugePages:        37 kB
                    ShmemPmdMapped:        38 kB
                    CmaTotal:              39 kB
                    CmaFree:               40 kB
                    HugePages_Total:       41 kB
                    HugePages_Free:        42 kB
                    HugePages_Rsvd:        43 kB
                    HugePages_Surp:        44 kB
                    Hugepagesize:          45 kB
                    DirectMap46k:          46 kB
                    DirectMap47M:          47 kB
                    DirectMap48G:          48 kB
                    """).encode())
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, create=True, side_effect=open_mock) as m:
            mem = psutil.virtual_memory()
            assert m.called
            self.assertEqual(mem.total, 100 * 1024)
            self.assertEqual(mem.free, 2 * 1024)
            self.assertEqual(mem.buffers, 4 * 1024)
            # cached mem also includes reclaimable memory
            self.assertEqual(mem.cached, (5 + 23) * 1024)
            self.assertEqual(mem.shared, 21 * 1024)
            self.assertEqual(mem.active, 7 * 1024)
            self.assertEqual(mem.inactive, 8 * 1024)
            self.assertEqual(mem.slab, 22 * 1024)
            self.assertEqual(mem.available, 3 * 1024)


# =====================================================================
# --- system swap memory
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemSwapMemory(PsutilTestCase):

    @staticmethod
    def meminfo_has_swap_info():
        """Return True if /proc/meminfo provides swap metrics."""
        with open("/proc/meminfo") as f:
            data = f.read()
        return 'SwapTotal:' in data and 'SwapFree:' in data

    def test_total(self):
        free_value = free_swap().total
        psutil_value = psutil.swap_memory().total
        return self.assertAlmostEqual(
            free_value, psutil_value, delta=TOLERANCE_SYS_MEM)

    @retry_on_failure()
    def test_used(self):
        free_value = free_swap().used
        psutil_value = psutil.swap_memory().used
        return self.assertAlmostEqual(
            free_value, psutil_value, delta=TOLERANCE_SYS_MEM)

    @retry_on_failure()
    def test_free(self):
        free_value = free_swap().free
        psutil_value = psutil.swap_memory().free
        return self.assertAlmostEqual(
            free_value, psutil_value, delta=TOLERANCE_SYS_MEM)

    def test_missing_sin_sout(self):
        with mock.patch('psutil._common.open', create=True) as m:
            with warnings.catch_warnings(record=True) as ws:
                warnings.simplefilter("always")
                ret = psutil.swap_memory()
                assert m.called
                self.assertEqual(len(ws), 1)
                w = ws[0]
                assert w.filename.endswith('psutil/_pslinux.py')
                self.assertIn(
                    "'sin' and 'sout' swap memory stats couldn't "
                    "be determined", str(w.message))
                self.assertEqual(ret.sin, 0)
                self.assertEqual(ret.sout, 0)

    def test_no_vmstat_mocked(self):
        # see https://github.com/giampaolo/psutil/issues/722
        with mock_open_exception(
                "/proc/vmstat",
                IOError(errno.ENOENT, 'no such file or directory')) as m:
            with warnings.catch_warnings(record=True) as ws:
                warnings.simplefilter("always")
                ret = psutil.swap_memory()
                assert m.called
                self.assertEqual(len(ws), 1)
                w = ws[0]
                assert w.filename.endswith('psutil/_pslinux.py')
                self.assertIn(
                    "'sin' and 'sout' swap memory stats couldn't "
                    "be determined and were set to 0",
                    str(w.message))
                self.assertEqual(ret.sin, 0)
                self.assertEqual(ret.sout, 0)

    def test_meminfo_against_sysinfo(self):
        # Make sure the content of /proc/meminfo about swap memory
        # matches sysinfo() syscall, see:
        # https://github.com/giampaolo/psutil/issues/1015
        if not self.meminfo_has_swap_info():
            return unittest.skip("/proc/meminfo has no swap metrics")
        with mock.patch('psutil._pslinux.cext.linux_sysinfo') as m:
            swap = psutil.swap_memory()
        assert not m.called
        import psutil._psutil_linux as cext
        _, _, _, _, total, free, unit_multiplier = cext.linux_sysinfo()
        total *= unit_multiplier
        free *= unit_multiplier
        self.assertEqual(swap.total, total)
        self.assertAlmostEqual(swap.free, free, delta=TOLERANCE_SYS_MEM)

    def test_emulate_meminfo_has_no_metrics(self):
        # Emulate a case where /proc/meminfo provides no swap metrics
        # in which case sysinfo() syscall is supposed to be used
        # as a fallback.
        with mock_open_content("/proc/meminfo", b"") as m:
            psutil.swap_memory()
            assert m.called


# =====================================================================
# --- system CPU
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemCPUTimes(PsutilTestCase):

    @unittest.skipIf(TRAVIS, "unknown failure on travis")
    def test_fields(self):
        fields = psutil.cpu_times()._fields
        kernel_ver = re.findall(r'\d+\.\d+\.\d+', os.uname()[2])[0]
        kernel_ver_info = tuple(map(int, kernel_ver.split('.')))
        if kernel_ver_info >= (2, 6, 11):
            self.assertIn('steal', fields)
        else:
            self.assertNotIn('steal', fields)
        if kernel_ver_info >= (2, 6, 24):
            self.assertIn('guest', fields)
        else:
            self.assertNotIn('guest', fields)
        if kernel_ver_info >= (3, 2, 0):
            self.assertIn('guest_nice', fields)
        else:
            self.assertNotIn('guest_nice', fields)


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemCPUCountLogical(PsutilTestCase):

    @unittest.skipIf(not os.path.exists("/sys/devices/system/cpu/online"),
                     "/sys/devices/system/cpu/online does not exist")
    def test_against_sysdev_cpu_online(self):
        with open("/sys/devices/system/cpu/online") as f:
            value = f.read().strip()
        if "-" in str(value):
            value = int(value.split('-')[1]) + 1
            self.assertEqual(psutil.cpu_count(), value)

    @unittest.skipIf(not os.path.exists("/sys/devices/system/cpu"),
                     "/sys/devices/system/cpu does not exist")
    def test_against_sysdev_cpu_num(self):
        ls = os.listdir("/sys/devices/system/cpu")
        count = len([x for x in ls if re.search(r"cpu\d+$", x) is not None])
        self.assertEqual(psutil.cpu_count(), count)

    @unittest.skipIf(not which("nproc"), "nproc utility not available")
    def test_against_nproc(self):
        num = int(sh("nproc --all"))
        self.assertEqual(psutil.cpu_count(logical=True), num)

    @unittest.skipIf(not which("lscpu"), "lscpu utility not available")
    def test_against_lscpu(self):
        out = sh("lscpu -p")
        num = len([x for x in out.split('\n') if not x.startswith('#')])
        self.assertEqual(psutil.cpu_count(logical=True), num)

    def test_emulate_fallbacks(self):
        import psutil._pslinux
        original = psutil._pslinux.cpu_count_logical()
        # Here we want to mock os.sysconf("SC_NPROCESSORS_ONLN") in
        # order to cause the parsing of /proc/cpuinfo and /proc/stat.
        with mock.patch(
                'psutil._pslinux.os.sysconf', side_effect=ValueError) as m:
            self.assertEqual(psutil._pslinux.cpu_count_logical(), original)
            assert m.called

            # Let's have open() return emtpy data and make sure None is
            # returned ('cause we mimick os.cpu_count()).
            with mock.patch('psutil._common.open', create=True) as m:
                self.assertIsNone(psutil._pslinux.cpu_count_logical())
                self.assertEqual(m.call_count, 2)
                # /proc/stat should be the last one
                self.assertEqual(m.call_args[0][0], '/proc/stat')

            # Let's push this a bit further and make sure /proc/cpuinfo
            # parsing works as expected.
            with open('/proc/cpuinfo', 'rb') as f:
                cpuinfo_data = f.read()
            fake_file = io.BytesIO(cpuinfo_data)
            with mock.patch('psutil._common.open',
                            return_value=fake_file, create=True) as m:
                self.assertEqual(psutil._pslinux.cpu_count_logical(), original)

            # Finally, let's make /proc/cpuinfo return meaningless data;
            # this way we'll fall back on relying on /proc/stat
            with mock_open_content('/proc/cpuinfo', b"") as m:
                self.assertEqual(psutil._pslinux.cpu_count_logical(), original)
                m.called


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemCPUCountPhysical(PsutilTestCase):

    @unittest.skipIf(not which("lscpu"), "lscpu utility not available")
    def test_against_lscpu(self):
        out = sh("lscpu -p")
        core_ids = set()
        for line in out.split('\n'):
            if not line.startswith('#'):
                fields = line.split(',')
                core_ids.add(fields[1])
        self.assertEqual(psutil.cpu_count(logical=False), len(core_ids))

    def test_method_2(self):
        meth_1 = psutil._pslinux.cpu_count_physical()
        with mock.patch('glob.glob', return_value=[]) as m:
            meth_2 = psutil._pslinux.cpu_count_physical()
            assert m.called
        if meth_1 is not None:
            self.assertEqual(meth_1, meth_2)

    def test_emulate_none(self):
        with mock.patch('glob.glob', return_value=[]) as m1:
            with mock.patch('psutil._common.open', create=True) as m2:
                self.assertIsNone(psutil._pslinux.cpu_count_physical())
        assert m1.called
        assert m2.called


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemCPUFrequency(PsutilTestCase):

    @unittest.skipIf(TRAVIS, "fails on Travis")
    @unittest.skipIf(not HAS_CPU_FREQ, "not supported")
    def test_emulate_use_second_file(self):
        # https://github.com/giampaolo/psutil/issues/981
        def path_exists_mock(path):
            if path.startswith("/sys/devices/system/cpu/cpufreq/policy"):
                return False
            else:
                return orig_exists(path)

        orig_exists = os.path.exists
        with mock.patch("os.path.exists", side_effect=path_exists_mock,
                        create=True):
            assert psutil.cpu_freq()

    @unittest.skipIf(not HAS_CPU_FREQ, "not supported")
    def test_emulate_use_cpuinfo(self):
        # Emulate a case where /sys/devices/system/cpu/cpufreq* does not
        # exist and /proc/cpuinfo is used instead.
        def path_exists_mock(path):
            if path.startswith('/sys/devices/system/cpu/'):
                return False
            else:
                if path == "/proc/cpuinfo":
                    flags.append(None)
                return os_path_exists(path)

        flags = []
        os_path_exists = os.path.exists
        try:
            with mock.patch("os.path.exists", side_effect=path_exists_mock):
                reload_module(psutil._pslinux)
                ret = psutil.cpu_freq()
                assert ret
                assert flags
                self.assertEqual(ret.max, 0.0)
                self.assertEqual(ret.min, 0.0)
                for freq in psutil.cpu_freq(percpu=True):
                    self.assertEqual(ret.max, 0.0)
                    self.assertEqual(ret.min, 0.0)
        finally:
            reload_module(psutil._pslinux)
            reload_module(psutil)

    @unittest.skipIf(not HAS_CPU_FREQ, "not supported")
    def test_emulate_data(self):
        def open_mock(name, *args, **kwargs):
            if (name.endswith('/scaling_cur_freq') and
                    name.startswith("/sys/devices/system/cpu/cpufreq/policy")):
                return io.BytesIO(b"500000")
            elif (name.endswith('/scaling_min_freq') and
                    name.startswith("/sys/devices/system/cpu/cpufreq/policy")):
                return io.BytesIO(b"600000")
            elif (name.endswith('/scaling_max_freq') and
                    name.startswith("/sys/devices/system/cpu/cpufreq/policy")):
                return io.BytesIO(b"700000")
            elif name == '/proc/cpuinfo':
                return io.BytesIO(b"cpu MHz		: 500")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock):
            with mock.patch(
                    'os.path.exists', return_value=True):
                freq = psutil.cpu_freq()
                self.assertEqual(freq.current, 500.0)
                # when /proc/cpuinfo is used min and max frequencies are not
                # available and are set to 0.
                if freq.min != 0.0:
                    self.assertEqual(freq.min, 600.0)
                if freq.max != 0.0:
                    self.assertEqual(freq.max, 700.0)

    @unittest.skipIf(not HAS_CPU_FREQ, "not supported")
    def test_emulate_multi_cpu(self):
        def open_mock(name, *args, **kwargs):
            n = name
            if (n.endswith('/scaling_cur_freq') and
                    n.startswith("/sys/devices/system/cpu/cpufreq/policy0")):
                return io.BytesIO(b"100000")
            elif (n.endswith('/scaling_min_freq') and
                    n.startswith("/sys/devices/system/cpu/cpufreq/policy0")):
                return io.BytesIO(b"200000")
            elif (n.endswith('/scaling_max_freq') and
                    n.startswith("/sys/devices/system/cpu/cpufreq/policy0")):
                return io.BytesIO(b"300000")
            elif (n.endswith('/scaling_cur_freq') and
                    n.startswith("/sys/devices/system/cpu/cpufreq/policy1")):
                return io.BytesIO(b"400000")
            elif (n.endswith('/scaling_min_freq') and
                    n.startswith("/sys/devices/system/cpu/cpufreq/policy1")):
                return io.BytesIO(b"500000")
            elif (n.endswith('/scaling_max_freq') and
                    n.startswith("/sys/devices/system/cpu/cpufreq/policy1")):
                return io.BytesIO(b"600000")
            elif name == '/proc/cpuinfo':
                return io.BytesIO(b"cpu MHz		: 100\n"
                                  b"cpu MHz		: 400")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock):
            with mock.patch('os.path.exists', return_value=True):
                with mock.patch('psutil._pslinux.cpu_count_logical',
                                return_value=2):
                    freq = psutil.cpu_freq(percpu=True)
                    self.assertEqual(freq[0].current, 100.0)
                    if freq[0].min != 0.0:
                        self.assertEqual(freq[0].min, 200.0)
                    if freq[0].max != 0.0:
                        self.assertEqual(freq[0].max, 300.0)
                    self.assertEqual(freq[1].current, 400.0)
                    if freq[1].min != 0.0:
                        self.assertEqual(freq[1].min, 500.0)
                    if freq[1].max != 0.0:
                        self.assertEqual(freq[1].max, 600.0)

    @unittest.skipIf(TRAVIS, "fails on Travis")
    @unittest.skipIf(not HAS_CPU_FREQ, "not supported")
    def test_emulate_no_scaling_cur_freq_file(self):
        # See: https://github.com/giampaolo/psutil/issues/1071
        def open_mock(name, *args, **kwargs):
            if name.endswith('/scaling_cur_freq'):
                raise IOError(errno.ENOENT, "")
            elif name.endswith('/cpuinfo_cur_freq'):
                return io.BytesIO(b"200000")
            elif name == '/proc/cpuinfo':
                return io.BytesIO(b"cpu MHz		: 200")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock):
            with mock.patch('os.path.exists', return_value=True):
                with mock.patch('psutil._pslinux.cpu_count_logical',
                                return_value=1):
                    freq = psutil.cpu_freq()
                    self.assertEqual(freq.current, 200)


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemCPUStats(PsutilTestCase):

    @unittest.skipIf(TRAVIS, "fails on Travis")
    def test_ctx_switches(self):
        vmstat_value = vmstat("context switches")
        psutil_value = psutil.cpu_stats().ctx_switches
        self.assertAlmostEqual(vmstat_value, psutil_value, delta=500)

    @unittest.skipIf(TRAVIS, "fails on Travis")
    def test_interrupts(self):
        vmstat_value = vmstat("interrupts")
        psutil_value = psutil.cpu_stats().interrupts
        self.assertAlmostEqual(vmstat_value, psutil_value, delta=500)


@unittest.skipIf(not LINUX, "LINUX only")
class TestLoadAvg(PsutilTestCase):

    @unittest.skipIf(not HAS_GETLOADAVG, "not supported")
    def test_getloadavg(self):
        psutil_value = psutil.getloadavg()
        with open("/proc/loadavg", "r") as f:
            proc_value = f.read().split()

        self.assertAlmostEqual(float(proc_value[0]), psutil_value[0], delta=1)
        self.assertAlmostEqual(float(proc_value[1]), psutil_value[1], delta=1)
        self.assertAlmostEqual(float(proc_value[2]), psutil_value[2], delta=1)


# =====================================================================
# --- system network
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemNetIfAddrs(PsutilTestCase):

    def test_ips(self):
        for name, addrs in psutil.net_if_addrs().items():
            for addr in addrs:
                if addr.family == psutil.AF_LINK:
                    self.assertEqual(addr.address, get_mac_address(name))
                elif addr.family == socket.AF_INET:
                    self.assertEqual(addr.address, get_ipv4_address(name))
                    self.assertEqual(addr.netmask, get_ipv4_netmask(name))
                    if addr.broadcast is not None:
                        self.assertEqual(addr.broadcast,
                                         get_ipv4_broadcast(name))
                    else:
                        self.assertEqual(get_ipv4_broadcast(name), '0.0.0.0')
                elif addr.family == socket.AF_INET6:
                    # IPv6 addresses can have a percent symbol at the end.
                    # E.g. these 2 are equivalent:
                    # "fe80::1ff:fe23:4567:890a"
                    # "fe80::1ff:fe23:4567:890a%eth0"
                    # That is the "zone id" portion, which usually is the name
                    # of the network interface.
                    address = addr.address.split('%')[0]
                    self.assertEqual(address, get_ipv6_address(name))

    # XXX - not reliable when having virtual NICs installed by Docker.
    # @unittest.skipIf(not which('ip'), "'ip' utility not available")
    # @unittest.skipIf(TRAVIS, "skipped on Travis")
    # def test_net_if_names(self):
    #     out = sh("ip addr").strip()
    #     nics = [x for x in psutil.net_if_addrs().keys() if ':' not in x]
    #     found = 0
    #     for line in out.split('\n'):
    #         line = line.strip()
    #         if re.search(r"^\d+:", line):
    #             found += 1
    #             name = line.split(':')[1].strip()
    #             self.assertIn(name, nics)
    #     self.assertEqual(len(nics), found, msg="%s\n---\n%s" % (
    #         pprint.pformat(nics), out))


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemNetIfStats(PsutilTestCase):

    def test_against_ifconfig(self):
        for name, stats in psutil.net_if_stats().items():
            try:
                out = sh("ifconfig %s" % name)
            except RuntimeError:
                pass
            else:
                self.assertEqual(stats.isup, 'RUNNING' in out, msg=out)
                self.assertEqual(stats.mtu,
                                 int(re.findall(r'(?i)MTU[: ](\d+)', out)[0]))

    def test_mtu(self):
        for name, stats in psutil.net_if_stats().items():
            with open("/sys/class/net/%s/mtu" % name, "rt") as f:
                self.assertEqual(stats.mtu, int(f.read().strip()))


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemNetIOCounters(PsutilTestCase):

    @retry_on_failure()
    def test_against_ifconfig(self):
        def ifconfig(nic):
            ret = {}
            out = sh("ifconfig %s" % name)
            ret['packets_recv'] = int(
                re.findall(r'RX packets[: ](\d+)', out)[0])
            ret['packets_sent'] = int(
                re.findall(r'TX packets[: ](\d+)', out)[0])
            ret['errin'] = int(re.findall(r'errors[: ](\d+)', out)[0])
            ret['errout'] = int(re.findall(r'errors[: ](\d+)', out)[1])
            ret['dropin'] = int(re.findall(r'dropped[: ](\d+)', out)[0])
            ret['dropout'] = int(re.findall(r'dropped[: ](\d+)', out)[1])
            ret['bytes_recv'] = int(
                re.findall(r'RX (?:packets \d+ +)?bytes[: ](\d+)', out)[0])
            ret['bytes_sent'] = int(
                re.findall(r'TX (?:packets \d+ +)?bytes[: ](\d+)', out)[0])
            return ret

        nio = psutil.net_io_counters(pernic=True, nowrap=False)
        for name, stats in nio.items():
            try:
                ifconfig_ret = ifconfig(name)
            except RuntimeError:
                continue
            self.assertAlmostEqual(
                stats.bytes_recv, ifconfig_ret['bytes_recv'], delta=1024 * 5)
            self.assertAlmostEqual(
                stats.bytes_sent, ifconfig_ret['bytes_sent'], delta=1024 * 5)
            self.assertAlmostEqual(
                stats.packets_recv, ifconfig_ret['packets_recv'], delta=1024)
            self.assertAlmostEqual(
                stats.packets_sent, ifconfig_ret['packets_sent'], delta=1024)
            self.assertAlmostEqual(
                stats.errin, ifconfig_ret['errin'], delta=10)
            self.assertAlmostEqual(
                stats.errout, ifconfig_ret['errout'], delta=10)
            self.assertAlmostEqual(
                stats.dropin, ifconfig_ret['dropin'], delta=10)
            self.assertAlmostEqual(
                stats.dropout, ifconfig_ret['dropout'], delta=10)


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemNetConnections(PsutilTestCase):

    @mock.patch('psutil._pslinux.socket.inet_ntop', side_effect=ValueError)
    @mock.patch('psutil._pslinux.supports_ipv6', return_value=False)
    def test_emulate_ipv6_unsupported(self, supports_ipv6, inet_ntop):
        # see: https://github.com/giampaolo/psutil/issues/623
        try:
            s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
            self.addCleanup(s.close)
            s.bind(("::1", 0))
        except socket.error:
            pass
        psutil.net_connections(kind='inet6')

    def test_emulate_unix(self):
        with mock_open_content(
            '/proc/net/unix',
            textwrap.dedent("""\
                0: 00000003 000 000 0001 03 462170 @/tmp/dbus-Qw2hMPIU3n
                0: 00000003 000 000 0001 03 35010 @/tmp/dbus-tB2X8h69BQ
                0: 00000003 000 000 0001 03 34424 @/tmp/dbus-cHy80Y8O
                000000000000000000000000000000000000000000000000000000
                """)) as m:
            psutil.net_connections(kind='unix')
            assert m.called


# =====================================================================
# --- system disks
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemDiskPartitions(PsutilTestCase):

    @unittest.skipIf(not hasattr(os, 'statvfs'), "os.statvfs() not available")
    @skip_on_not_implemented()
    def test_against_df(self):
        # test psutil.disk_usage() and psutil.disk_partitions()
        # against "df -a"
        def df(path):
            out = sh('df -P -B 1 "%s"' % path).strip()
            lines = out.split('\n')
            lines.pop(0)
            line = lines.pop(0)
            dev, total, used, free = line.split()[:4]
            if dev == 'none':
                dev = ''
            total, used, free = int(total), int(used), int(free)
            return dev, total, used, free

        for part in psutil.disk_partitions(all=False):
            usage = psutil.disk_usage(part.mountpoint)
            dev, total, used, free = df(part.mountpoint)
            self.assertEqual(usage.total, total)
            self.assertAlmostEqual(usage.free, free,
                                   delta=TOLERANCE_DISK_USAGE)
            self.assertAlmostEqual(usage.used, used,
                                   delta=TOLERANCE_DISK_USAGE)

    def test_zfs_fs(self):
        # Test that ZFS partitions are returned.
        with open("/proc/filesystems", "r") as f:
            data = f.read()
        if 'zfs' in data:
            for part in psutil.disk_partitions():
                if part.fstype == 'zfs':
                    break
            else:
                self.fail("couldn't find any ZFS partition")
        else:
            # No ZFS partitions on this system. Let's fake one.
            fake_file = io.StringIO(u("nodev\tzfs\n"))
            with mock.patch('psutil._common.open',
                            return_value=fake_file, create=True) as m1:
                with mock.patch(
                        'psutil._pslinux.cext.disk_partitions',
                        return_value=[('/dev/sdb3', '/', 'zfs', 'rw')]) as m2:
                    ret = psutil.disk_partitions()
                    assert m1.called
                    assert m2.called
                    assert ret
                    self.assertEqual(ret[0].fstype, 'zfs')

    def test_emulate_realpath_fail(self):
        # See: https://github.com/giampaolo/psutil/issues/1307
        try:
            with mock.patch('os.path.realpath',
                            return_value='/non/existent') as m:
                with self.assertRaises(FileNotFoundError):
                    psutil.disk_partitions()
                assert m.called
        finally:
            psutil.PROCFS_PATH = "/proc"


@unittest.skipIf(not LINUX, "LINUX only")
class TestSystemDiskIoCounters(PsutilTestCase):

    def test_emulate_kernel_2_4(self):
        # Tests /proc/diskstats parsing format for 2.4 kernels, see:
        # https://github.com/giampaolo/psutil/issues/767
        with mock_open_content(
                '/proc/diskstats',
                "   3     0   1 hda 2 3 4 5 6 7 8 9 10 11 12"):
            with mock.patch('psutil._pslinux.is_storage_device',
                            return_value=True):
                ret = psutil.disk_io_counters(nowrap=False)
                self.assertEqual(ret.read_count, 1)
                self.assertEqual(ret.read_merged_count, 2)
                self.assertEqual(ret.read_bytes, 3 * SECTOR_SIZE)
                self.assertEqual(ret.read_time, 4)
                self.assertEqual(ret.write_count, 5)
                self.assertEqual(ret.write_merged_count, 6)
                self.assertEqual(ret.write_bytes, 7 * SECTOR_SIZE)
                self.assertEqual(ret.write_time, 8)
                self.assertEqual(ret.busy_time, 10)

    def test_emulate_kernel_2_6_full(self):
        # Tests /proc/diskstats parsing format for 2.6 kernels,
        # lines reporting all metrics:
        # https://github.com/giampaolo/psutil/issues/767
        with mock_open_content(
                '/proc/diskstats',
                "   3    0   hda 1 2 3 4 5 6 7 8 9 10 11"):
            with mock.patch('psutil._pslinux.is_storage_device',
                            return_value=True):
                ret = psutil.disk_io_counters(nowrap=False)
                self.assertEqual(ret.read_count, 1)
                self.assertEqual(ret.read_merged_count, 2)
                self.assertEqual(ret.read_bytes, 3 * SECTOR_SIZE)
                self.assertEqual(ret.read_time, 4)
                self.assertEqual(ret.write_count, 5)
                self.assertEqual(ret.write_merged_count, 6)
                self.assertEqual(ret.write_bytes, 7 * SECTOR_SIZE)
                self.assertEqual(ret.write_time, 8)
                self.assertEqual(ret.busy_time, 10)

    def test_emulate_kernel_2_6_limited(self):
        # Tests /proc/diskstats parsing format for 2.6 kernels,
        # where one line of /proc/partitions return a limited
        # amount of metrics when it bumps into a partition
        # (instead of a disk). See:
        # https://github.com/giampaolo/psutil/issues/767
        with mock_open_content(
                '/proc/diskstats',
                "   3    1   hda 1 2 3 4"):
            with mock.patch('psutil._pslinux.is_storage_device',
                            return_value=True):
                ret = psutil.disk_io_counters(nowrap=False)
                self.assertEqual(ret.read_count, 1)
                self.assertEqual(ret.read_bytes, 2 * SECTOR_SIZE)
                self.assertEqual(ret.write_count, 3)
                self.assertEqual(ret.write_bytes, 4 * SECTOR_SIZE)

                self.assertEqual(ret.read_merged_count, 0)
                self.assertEqual(ret.read_time, 0)
                self.assertEqual(ret.write_merged_count, 0)
                self.assertEqual(ret.write_time, 0)
                self.assertEqual(ret.busy_time, 0)

    def test_emulate_include_partitions(self):
        # Make sure that when perdisk=True disk partitions are returned,
        # see:
        # https://github.com/giampaolo/psutil/pull/1313#issuecomment-408626842
        with mock_open_content(
                '/proc/diskstats',
                textwrap.dedent("""\
                    3    0   nvme0n1 1 2 3 4 5 6 7 8 9 10 11
                    3    0   nvme0n1p1 1 2 3 4 5 6 7 8 9 10 11
                    """)):
            with mock.patch('psutil._pslinux.is_storage_device',
                            return_value=False):
                ret = psutil.disk_io_counters(perdisk=True, nowrap=False)
                self.assertEqual(len(ret), 2)
                self.assertEqual(ret['nvme0n1'].read_count, 1)
                self.assertEqual(ret['nvme0n1p1'].read_count, 1)
                self.assertEqual(ret['nvme0n1'].write_count, 5)
                self.assertEqual(ret['nvme0n1p1'].write_count, 5)

    def test_emulate_exclude_partitions(self):
        # Make sure that when perdisk=False partitions (e.g. 'sda1',
        # 'nvme0n1p1') are skipped and not included in the total count.
        # https://github.com/giampaolo/psutil/pull/1313#issuecomment-408626842
        with mock_open_content(
                '/proc/diskstats',
                textwrap.dedent("""\
                    3    0   nvme0n1 1 2 3 4 5 6 7 8 9 10 11
                    3    0   nvme0n1p1 1 2 3 4 5 6 7 8 9 10 11
                    """)):
            with mock.patch('psutil._pslinux.is_storage_device',
                            return_value=False):
                ret = psutil.disk_io_counters(perdisk=False, nowrap=False)
                self.assertIsNone(ret)

        #
        def is_storage_device(name):
            return name == 'nvme0n1'

        with mock_open_content(
                '/proc/diskstats',
                textwrap.dedent("""\
                    3    0   nvme0n1 1 2 3 4 5 6 7 8 9 10 11
                    3    0   nvme0n1p1 1 2 3 4 5 6 7 8 9 10 11
                    """)):
            with mock.patch('psutil._pslinux.is_storage_device',
                            create=True, side_effect=is_storage_device):
                ret = psutil.disk_io_counters(perdisk=False, nowrap=False)
                self.assertEqual(ret.read_count, 1)
                self.assertEqual(ret.write_count, 5)

    def test_emulate_use_sysfs(self):
        def exists(path):
            if path == '/proc/diskstats':
                return False
            return True

        wprocfs = psutil.disk_io_counters(perdisk=True)
        with mock.patch('psutil._pslinux.os.path.exists',
                        create=True, side_effect=exists):
            wsysfs = psutil.disk_io_counters(perdisk=True)
        self.assertEqual(len(wprocfs), len(wsysfs))

    def test_emulate_not_impl(self):
        def exists(path):
            return False

        with mock.patch('psutil._pslinux.os.path.exists',
                        create=True, side_effect=exists):
            self.assertRaises(NotImplementedError, psutil.disk_io_counters)


# =====================================================================
# --- misc
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestMisc(PsutilTestCase):

    def test_boot_time(self):
        vmstat_value = vmstat('boot time')
        psutil_value = psutil.boot_time()
        self.assertEqual(int(vmstat_value), int(psutil_value))

    def test_no_procfs_on_import(self):
        my_procfs = self.get_testfn()
        os.mkdir(my_procfs)

        with open(os.path.join(my_procfs, 'stat'), 'w') as f:
            f.write('cpu   0 0 0 0 0 0 0 0 0 0\n')
            f.write('cpu0  0 0 0 0 0 0 0 0 0 0\n')
            f.write('cpu1  0 0 0 0 0 0 0 0 0 0\n')

        try:
            orig_open = open

            def open_mock(name, *args, **kwargs):
                if name.startswith('/proc'):
                    raise IOError(errno.ENOENT, 'rejecting access for test')
                return orig_open(name, *args, **kwargs)

            patch_point = 'builtins.open' if PY3 else '__builtin__.open'
            with mock.patch(patch_point, side_effect=open_mock):
                reload_module(psutil)

                self.assertRaises(IOError, psutil.cpu_times)
                self.assertRaises(IOError, psutil.cpu_times, percpu=True)
                self.assertRaises(IOError, psutil.cpu_percent)
                self.assertRaises(IOError, psutil.cpu_percent, percpu=True)
                self.assertRaises(IOError, psutil.cpu_times_percent)
                self.assertRaises(
                    IOError, psutil.cpu_times_percent, percpu=True)

                psutil.PROCFS_PATH = my_procfs

                self.assertEqual(psutil.cpu_percent(), 0)
                self.assertEqual(sum(psutil.cpu_times_percent()), 0)

                # since we don't know the number of CPUs at import time,
                # we awkwardly say there are none until the second call
                per_cpu_percent = psutil.cpu_percent(percpu=True)
                self.assertEqual(sum(per_cpu_percent), 0)

                # ditto awkward length
                per_cpu_times_percent = psutil.cpu_times_percent(percpu=True)
                self.assertEqual(sum(map(sum, per_cpu_times_percent)), 0)

                # much user, very busy
                with open(os.path.join(my_procfs, 'stat'), 'w') as f:
                    f.write('cpu   1 0 0 0 0 0 0 0 0 0\n')
                    f.write('cpu0  1 0 0 0 0 0 0 0 0 0\n')
                    f.write('cpu1  1 0 0 0 0 0 0 0 0 0\n')

                self.assertNotEqual(psutil.cpu_percent(), 0)
                self.assertNotEqual(
                    sum(psutil.cpu_percent(percpu=True)), 0)
                self.assertNotEqual(sum(psutil.cpu_times_percent()), 0)
                self.assertNotEqual(
                    sum(map(sum, psutil.cpu_times_percent(percpu=True))), 0)
        finally:
            shutil.rmtree(my_procfs)
            reload_module(psutil)

        self.assertEqual(psutil.PROCFS_PATH, '/proc')

    def test_cpu_steal_decrease(self):
        # Test cumulative cpu stats decrease. We should ignore this.
        # See issue #1210.
        with mock_open_content(
            "/proc/stat",
            textwrap.dedent("""\
                cpu   0 0 0 0 0 0 0 1 0 0
                cpu0  0 0 0 0 0 0 0 1 0 0
                cpu1  0 0 0 0 0 0 0 1 0 0
                """).encode()) as m:
            # first call to "percent" functions should read the new stat file
            # and compare to the "real" file read at import time - so the
            # values are meaningless
            psutil.cpu_percent()
            assert m.called
            psutil.cpu_percent(percpu=True)
            psutil.cpu_times_percent()
            psutil.cpu_times_percent(percpu=True)

        with mock_open_content(
            "/proc/stat",
            textwrap.dedent("""\
                cpu   1 0 0 0 0 0 0 0 0 0
                cpu0  1 0 0 0 0 0 0 0 0 0
                cpu1  1 0 0 0 0 0 0 0 0 0
                """).encode()) as m:
            # Increase "user" while steal goes "backwards" to zero.
            cpu_percent = psutil.cpu_percent()
            assert m.called
            cpu_percent_percpu = psutil.cpu_percent(percpu=True)
            cpu_times_percent = psutil.cpu_times_percent()
            cpu_times_percent_percpu = psutil.cpu_times_percent(percpu=True)
            self.assertNotEqual(cpu_percent, 0)
            self.assertNotEqual(sum(cpu_percent_percpu), 0)
            self.assertNotEqual(sum(cpu_times_percent), 0)
            self.assertNotEqual(sum(cpu_times_percent), 100.0)
            self.assertNotEqual(sum(map(sum, cpu_times_percent_percpu)), 0)
            self.assertNotEqual(sum(map(sum, cpu_times_percent_percpu)), 100.0)
            self.assertEqual(cpu_times_percent.steal, 0)
            self.assertNotEqual(cpu_times_percent.user, 0)

    def test_boot_time_mocked(self):
        with mock.patch('psutil._common.open', create=True) as m:
            self.assertRaises(
                RuntimeError,
                psutil._pslinux.boot_time)
            assert m.called

    def test_users_mocked(self):
        # Make sure ':0' and ':0.0' (returned by C ext) are converted
        # to 'localhost'.
        with mock.patch('psutil._pslinux.cext.users',
                        return_value=[('giampaolo', 'pts/2', ':0',
                                       1436573184.0, True, 2)]) as m:
            self.assertEqual(psutil.users()[0].host, 'localhost')
            assert m.called
        with mock.patch('psutil._pslinux.cext.users',
                        return_value=[('giampaolo', 'pts/2', ':0.0',
                                       1436573184.0, True, 2)]) as m:
            self.assertEqual(psutil.users()[0].host, 'localhost')
            assert m.called
        # ...otherwise it should be returned as-is
        with mock.patch('psutil._pslinux.cext.users',
                        return_value=[('giampaolo', 'pts/2', 'foo',
                                       1436573184.0, True, 2)]) as m:
            self.assertEqual(psutil.users()[0].host, 'foo')
            assert m.called

    def test_procfs_path(self):
        tdir = self.get_testfn()
        os.mkdir(tdir)
        try:
            psutil.PROCFS_PATH = tdir
            self.assertRaises(IOError, psutil.virtual_memory)
            self.assertRaises(IOError, psutil.cpu_times)
            self.assertRaises(IOError, psutil.cpu_times, percpu=True)
            self.assertRaises(IOError, psutil.boot_time)
            # self.assertRaises(IOError, psutil.pids)
            self.assertRaises(IOError, psutil.net_connections)
            self.assertRaises(IOError, psutil.net_io_counters)
            self.assertRaises(IOError, psutil.net_if_stats)
            # self.assertRaises(IOError, psutil.disk_io_counters)
            self.assertRaises(IOError, psutil.disk_partitions)
            self.assertRaises(psutil.NoSuchProcess, psutil.Process)
        finally:
            psutil.PROCFS_PATH = "/proc"

    @retry_on_failure()
    def test_issue_687(self):
        # In case of thread ID:
        # - pid_exists() is supposed to return False
        # - Process(tid) is supposed to work
        # - pids() should not return the TID
        # See: https://github.com/giampaolo/psutil/issues/687
        t = ThreadTask()
        t.start()
        try:
            p = psutil.Process()
            threads = p.threads()
            self.assertEqual(len(threads), 2)
            tid = sorted(threads, key=lambda x: x.id)[1].id
            self.assertNotEqual(p.pid, tid)
            pt = psutil.Process(tid)
            pt.as_dict()
            self.assertNotIn(tid, psutil.pids())
        finally:
            t.stop()

    def test_pid_exists_no_proc_status(self):
        # Internally pid_exists relies on /proc/{pid}/status.
        # Emulate a case where this file is empty in which case
        # psutil is supposed to fall back on using pids().
        with mock_open_content("/proc/%s/status", "") as m:
            assert psutil.pid_exists(os.getpid())
            assert m.called


# =====================================================================
# --- sensors
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
@unittest.skipIf(not HAS_BATTERY, "no battery")
class TestSensorsBattery(PsutilTestCase):

    @unittest.skipIf(not which("acpi"), "acpi utility not available")
    def test_percent(self):
        out = sh("acpi -b")
        acpi_value = int(out.split(",")[1].strip().replace('%', ''))
        psutil_value = psutil.sensors_battery().percent
        self.assertAlmostEqual(acpi_value, psutil_value, delta=1)

    def test_emulate_power_plugged(self):
        # Pretend the AC power cable is connected.
        def open_mock(name, *args, **kwargs):
            if name.endswith("AC0/online") or name.endswith("AC/online"):
                return io.BytesIO(b"1")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock) as m:
            self.assertEqual(psutil.sensors_battery().power_plugged, True)
            self.assertEqual(
                psutil.sensors_battery().secsleft, psutil.POWER_TIME_UNLIMITED)
            assert m.called

    def test_emulate_power_plugged_2(self):
        # Same as above but pretend /AC0/online does not exist in which
        # case code relies on /status file.
        def open_mock(name, *args, **kwargs):
            if name.endswith("AC0/online") or name.endswith("AC/online"):
                raise IOError(errno.ENOENT, "")
            elif name.endswith("/status"):
                return io.StringIO(u("charging"))
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock) as m:
            self.assertEqual(psutil.sensors_battery().power_plugged, True)
            assert m.called

    def test_emulate_power_not_plugged(self):
        # Pretend the AC power cable is not connected.
        def open_mock(name, *args, **kwargs):
            if name.endswith("AC0/online") or name.endswith("AC/online"):
                return io.BytesIO(b"0")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock) as m:
            self.assertEqual(psutil.sensors_battery().power_plugged, False)
            assert m.called

    def test_emulate_power_not_plugged_2(self):
        # Same as above but pretend /AC0/online does not exist in which
        # case code relies on /status file.
        def open_mock(name, *args, **kwargs):
            if name.endswith("AC0/online") or name.endswith("AC/online"):
                raise IOError(errno.ENOENT, "")
            elif name.endswith("/status"):
                return io.StringIO(u("discharging"))
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock) as m:
            self.assertEqual(psutil.sensors_battery().power_plugged, False)
            assert m.called

    def test_emulate_power_undetermined(self):
        # Pretend we can't know whether the AC power cable not
        # connected (assert fallback to False).
        def open_mock(name, *args, **kwargs):
            if name.startswith("/sys/class/power_supply/AC0/online") or \
                    name.startswith("/sys/class/power_supply/AC/online"):
                raise IOError(errno.ENOENT, "")
            elif name.startswith("/sys/class/power_supply/BAT0/status"):
                return io.BytesIO(b"???")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock) as m:
            self.assertIsNone(psutil.sensors_battery().power_plugged)
            assert m.called

    def test_emulate_energy_full_0(self):
        # Emulate a case where energy_full files returns 0.
        with mock_open_content(
                "/sys/class/power_supply/BAT0/energy_full", b"0") as m:
            self.assertEqual(psutil.sensors_battery().percent, 0)
            assert m.called

    def test_emulate_energy_full_not_avail(self):
        # Emulate a case where energy_full file does not exist.
        # Expected fallback on /capacity.
        with mock_open_exception(
                "/sys/class/power_supply/BAT0/energy_full",
                IOError(errno.ENOENT, "")):
            with mock_open_exception(
                    "/sys/class/power_supply/BAT0/charge_full",
                    IOError(errno.ENOENT, "")):
                with mock_open_content(
                        "/sys/class/power_supply/BAT0/capacity", b"88"):
                    self.assertEqual(psutil.sensors_battery().percent, 88)

    def test_emulate_no_power(self):
        # Emulate a case where /AC0/online file nor /BAT0/status exist.
        with mock_open_exception(
                "/sys/class/power_supply/AC/online",
                IOError(errno.ENOENT, "")):
            with mock_open_exception(
                    "/sys/class/power_supply/AC0/online",
                    IOError(errno.ENOENT, "")):
                with mock_open_exception(
                        "/sys/class/power_supply/BAT0/status",
                        IOError(errno.ENOENT, "")):
                    self.assertIsNone(psutil.sensors_battery().power_plugged)


@unittest.skipIf(not LINUX, "LINUX only")
class TestSensorsBatteryEmulated(PsutilTestCase):

    def test_it(self):
        def open_mock(name, *args, **kwargs):
            if name.endswith("/energy_now"):
                return io.StringIO(u("60000000"))
            elif name.endswith("/power_now"):
                return io.StringIO(u("0"))
            elif name.endswith("/energy_full"):
                return io.StringIO(u("60000001"))
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch('os.listdir', return_value=["BAT0"]) as mlistdir:
            with mock.patch(patch_point, side_effect=open_mock) as mopen:
                self.assertIsNotNone(psutil.sensors_battery())
        assert mlistdir.called
        assert mopen.called


@unittest.skipIf(not LINUX, "LINUX only")
class TestSensorsTemperatures(PsutilTestCase):

    def test_emulate_class_hwmon(self):
        def open_mock(name, *args, **kwargs):
            if name.endswith('/name'):
                return io.StringIO(u("name"))
            elif name.endswith('/temp1_label'):
                return io.StringIO(u("label"))
            elif name.endswith('/temp1_input'):
                return io.BytesIO(b"30000")
            elif name.endswith('/temp1_max'):
                return io.BytesIO(b"40000")
            elif name.endswith('/temp1_crit'):
                return io.BytesIO(b"50000")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock):
            # Test case with /sys/class/hwmon
            with mock.patch('glob.glob',
                            return_value=['/sys/class/hwmon/hwmon0/temp1']):
                temp = psutil.sensors_temperatures()['name'][0]
                self.assertEqual(temp.label, 'label')
                self.assertEqual(temp.current, 30.0)
                self.assertEqual(temp.high, 40.0)
                self.assertEqual(temp.critical, 50.0)

    def test_emulate_class_thermal(self):
        def open_mock(name, *args, **kwargs):
            if name.endswith('0_temp'):
                return io.BytesIO(b"50000")
            elif name.endswith('temp'):
                return io.BytesIO(b"30000")
            elif name.endswith('0_type'):
                return io.StringIO(u("critical"))
            elif name.endswith('type'):
                return io.StringIO(u("name"))
            else:
                return orig_open(name, *args, **kwargs)

        def glob_mock(path):
            if path == '/sys/class/hwmon/hwmon*/temp*_*':
                return []
            elif path == '/sys/class/hwmon/hwmon*/device/temp*_*':
                return []
            elif path == '/sys/class/thermal/thermal_zone*':
                return ['/sys/class/thermal/thermal_zone0']
            elif path == '/sys/class/thermal/thermal_zone0/trip_point*':
                return ['/sys/class/thermal/thermal_zone1/trip_point_0_type',
                        '/sys/class/thermal/thermal_zone1/trip_point_0_temp']
            return []

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock):
            with mock.patch('glob.glob', create=True, side_effect=glob_mock):
                temp = psutil.sensors_temperatures()['name'][0]
                self.assertEqual(temp.label, '')
                self.assertEqual(temp.current, 30.0)
                self.assertEqual(temp.high, 50.0)
                self.assertEqual(temp.critical, 50.0)


@unittest.skipIf(not LINUX, "LINUX only")
class TestSensorsFans(PsutilTestCase):

    def test_emulate_data(self):
        def open_mock(name, *args, **kwargs):
            if name.endswith('/name'):
                return io.StringIO(u("name"))
            elif name.endswith('/fan1_label'):
                return io.StringIO(u("label"))
            elif name.endswith('/fan1_input'):
                return io.StringIO(u("2000"))
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock):
            with mock.patch('glob.glob',
                            return_value=['/sys/class/hwmon/hwmon2/fan1']):
                fan = psutil.sensors_fans()['name'][0]
                self.assertEqual(fan.label, 'label')
                self.assertEqual(fan.current, 2000)


# =====================================================================
# --- test process
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestProcess(PsutilTestCase):

    @retry_on_failure()
    def test_memory_full_info(self):
        testfn = self.get_testfn()
        src = textwrap.dedent("""
            import time
            with open("%s", "w") as f:
                time.sleep(10)
            """ % testfn)
        sproc = self.pyrun(src)
        call_until(lambda: os.listdir('.'), "'%s' not in ret" % testfn)
        p = psutil.Process(sproc.pid)
        time.sleep(.1)
        mem = p.memory_full_info()
        maps = p.memory_maps(grouped=False)
        self.assertAlmostEqual(
            mem.uss, sum([x.private_dirty + x.private_clean for x in maps]),
            delta=4096)
        self.assertAlmostEqual(
            mem.pss, sum([x.pss for x in maps]), delta=4096)
        self.assertAlmostEqual(
            mem.swap, sum([x.swap for x in maps]), delta=4096)

    def test_memory_full_info_mocked(self):
        # See: https://github.com/giampaolo/psutil/issues/1222
        with mock_open_content(
            "/proc/%s/smaps" % os.getpid(),
            textwrap.dedent("""\
                fffff0 r-xp 00000000 00:00 0                  [vsyscall]
                Size:                  1 kB
                Rss:                   2 kB
                Pss:                   3 kB
                Shared_Clean:          4 kB
                Shared_Dirty:          5 kB
                Private_Clean:         6 kB
                Private_Dirty:         7 kB
                Referenced:            8 kB
                Anonymous:             9 kB
                LazyFree:              10 kB
                AnonHugePages:         11 kB
                ShmemPmdMapped:        12 kB
                Shared_Hugetlb:        13 kB
                Private_Hugetlb:       14 kB
                Swap:                  15 kB
                SwapPss:               16 kB
                KernelPageSize:        17 kB
                MMUPageSize:           18 kB
                Locked:                19 kB
                VmFlags: rd ex
                """).encode()) as m:
            p = psutil.Process()
            mem = p.memory_full_info()
            assert m.called
            self.assertEqual(mem.uss, (6 + 7 + 14) * 1024)
            self.assertEqual(mem.pss, 3 * 1024)
            self.assertEqual(mem.swap, 15 * 1024)

    # On PYPY file descriptors are not closed fast enough.
    @unittest.skipIf(PYPY, "unreliable on PYPY")
    def test_open_files_mode(self):
        def get_test_file(fname):
            p = psutil.Process()
            giveup_at = time.time() + GLOBAL_TIMEOUT
            while True:
                for file in p.open_files():
                    if file.path == os.path.abspath(fname):
                        return file
                    elif time.time() > giveup_at:
                        break
            raise RuntimeError("timeout looking for test file")

        #
        testfn = self.get_testfn()
        with open(testfn, "w"):
            self.assertEqual(get_test_file(testfn).mode, "w")
        with open(testfn, "r"):
            self.assertEqual(get_test_file(testfn).mode, "r")
        with open(testfn, "a"):
            self.assertEqual(get_test_file(testfn).mode, "a")
        #
        with open(testfn, "r+"):
            self.assertEqual(get_test_file(testfn).mode, "r+")
        with open(testfn, "w+"):
            self.assertEqual(get_test_file(testfn).mode, "r+")
        with open(testfn, "a+"):
            self.assertEqual(get_test_file(testfn).mode, "a+")
        # note: "x" bit is not supported
        if PY3:
            safe_rmpath(testfn)
            with open(testfn, "x"):
                self.assertEqual(get_test_file(testfn).mode, "w")
            safe_rmpath(testfn)
            with open(testfn, "x+"):
                self.assertEqual(get_test_file(testfn).mode, "r+")

    def test_open_files_file_gone(self):
        # simulates a file which gets deleted during open_files()
        # execution
        p = psutil.Process()
        files = p.open_files()
        with open(self.get_testfn(), 'w'):
            # give the kernel some time to see the new file
            call_until(p.open_files, "len(ret) != %i" % len(files))
            with mock.patch('psutil._pslinux.os.readlink',
                            side_effect=OSError(errno.ENOENT, "")) as m:
                files = p.open_files()
                assert not files
                assert m.called
            # also simulate the case where os.readlink() returns EINVAL
            # in which case psutil is supposed to 'continue'
            with mock.patch('psutil._pslinux.os.readlink',
                            side_effect=OSError(errno.EINVAL, "")) as m:
                self.assertEqual(p.open_files(), [])
                assert m.called

    def test_open_files_fd_gone(self):
        # Simulate a case where /proc/{pid}/fdinfo/{fd} disappears
        # while iterating through fds.
        # https://travis-ci.org/giampaolo/psutil/jobs/225694530
        p = psutil.Process()
        files = p.open_files()
        with open(self.get_testfn(), 'w'):
            # give the kernel some time to see the new file
            call_until(p.open_files, "len(ret) != %i" % len(files))
            patch_point = 'builtins.open' if PY3 else '__builtin__.open'
            with mock.patch(patch_point,
                            side_effect=IOError(errno.ENOENT, "")) as m:
                files = p.open_files()
                assert not files
                assert m.called

    # --- mocked tests

    def test_terminal_mocked(self):
        with mock.patch('psutil._pslinux._psposix.get_terminal_map',
                        return_value={}) as m:
            self.assertIsNone(psutil._pslinux.Process(os.getpid()).terminal())
            assert m.called

    # TODO: re-enable this test.
    # def test_num_ctx_switches_mocked(self):
    #     with mock.patch('psutil._common.open', create=True) as m:
    #         self.assertRaises(
    #             NotImplementedError,
    #             psutil._pslinux.Process(os.getpid()).num_ctx_switches)
    #         assert m.called

    def test_cmdline_mocked(self):
        # see: https://github.com/giampaolo/psutil/issues/639
        p = psutil.Process()
        fake_file = io.StringIO(u('foo\x00bar\x00'))
        with mock.patch('psutil._common.open',
                        return_value=fake_file, create=True) as m:
            self.assertEqual(p.cmdline(), ['foo', 'bar'])
            assert m.called
        fake_file = io.StringIO(u('foo\x00bar\x00\x00'))
        with mock.patch('psutil._common.open',
                        return_value=fake_file, create=True) as m:
            self.assertEqual(p.cmdline(), ['foo', 'bar', ''])
            assert m.called

    def test_cmdline_spaces_mocked(self):
        # see: https://github.com/giampaolo/psutil/issues/1179
        p = psutil.Process()
        fake_file = io.StringIO(u('foo bar '))
        with mock.patch('psutil._common.open',
                        return_value=fake_file, create=True) as m:
            self.assertEqual(p.cmdline(), ['foo', 'bar'])
            assert m.called
        fake_file = io.StringIO(u('foo bar  '))
        with mock.patch('psutil._common.open',
                        return_value=fake_file, create=True) as m:
            self.assertEqual(p.cmdline(), ['foo', 'bar', ''])
            assert m.called

    def test_cmdline_mixed_separators(self):
        # https://github.com/giampaolo/psutil/issues/
        #    1179#issuecomment-552984549
        p = psutil.Process()
        fake_file = io.StringIO(u('foo\x20bar\x00'))
        with mock.patch('psutil._common.open',
                        return_value=fake_file, create=True) as m:
            self.assertEqual(p.cmdline(), ['foo', 'bar'])
            assert m.called

    def test_readlink_path_deleted_mocked(self):
        with mock.patch('psutil._pslinux.os.readlink',
                        return_value='/home/foo (deleted)'):
            self.assertEqual(psutil.Process().exe(), "/home/foo")
            self.assertEqual(psutil.Process().cwd(), "/home/foo")

    def test_threads_mocked(self):
        # Test the case where os.listdir() returns a file (thread)
        # which no longer exists by the time we open() it (race
        # condition). threads() is supposed to ignore that instead
        # of raising NSP.
        def open_mock(name, *args, **kwargs):
            if name.startswith('/proc/%s/task' % os.getpid()):
                raise IOError(errno.ENOENT, "")
            else:
                return orig_open(name, *args, **kwargs)

        orig_open = open
        patch_point = 'builtins.open' if PY3 else '__builtin__.open'
        with mock.patch(patch_point, side_effect=open_mock) as m:
            ret = psutil.Process().threads()
            assert m.called
            self.assertEqual(ret, [])

        # ...but if it bumps into something != ENOENT we want an
        # exception.
        def open_mock(name, *args, **kwargs):
            if name.startswith('/proc/%s/task' % os.getpid()):
                raise IOError(errno.EPERM, "")
            else:
                return orig_open(name, *args, **kwargs)

        with mock.patch(patch_point, side_effect=open_mock):
            self.assertRaises(psutil.AccessDenied, psutil.Process().threads)

    def test_exe_mocked(self):
        with mock.patch('psutil._pslinux.readlink',
                        side_effect=OSError(errno.ENOENT, "")) as m1:
            with mock.patch('psutil.Process.cmdline',
                            side_effect=psutil.AccessDenied(0, "")) as m2:
                # No such file error; might be raised also if /proc/pid/exe
                # path actually exists for system processes with low pids
                # (about 0-20). In this case psutil is supposed to return
                # an empty string.
                ret = psutil.Process().exe()
                assert m1.called
                assert m2.called
                self.assertEqual(ret, "")

                # ...but if /proc/pid no longer exist we're supposed to treat
                # it as an alias for zombie process
                with mock.patch('psutil._pslinux.os.path.lexists',
                                return_value=False):
                    self.assertRaises(
                        psutil.ZombieProcess, psutil.Process().exe)

    def test_issue_1014(self):
        # Emulates a case where smaps file does not exist. In this case
        # wrap_exception decorator should not raise NoSuchProcess.
        with mock_open_exception(
                '/proc/%s/smaps' % os.getpid(),
                IOError(errno.ENOENT, "")) as m:
            p = psutil.Process()
            with self.assertRaises(FileNotFoundError):
                p.memory_maps()
            assert m.called

    @unittest.skipIf(not HAS_RLIMIT, "not supported")
    def test_rlimit_zombie(self):
        # Emulate a case where rlimit() raises ENOSYS, which may
        # happen in case of zombie process:
        # https://travis-ci.org/giampaolo/psutil/jobs/51368273
        with mock.patch("psutil._pslinux.cext.linux_prlimit",
                        side_effect=OSError(errno.ENOSYS, "")) as m:
            p = psutil.Process()
            p.name()
            with self.assertRaises(psutil.ZombieProcess) as exc:
                p.rlimit(psutil.RLIMIT_NOFILE)
            assert m.called
        self.assertEqual(exc.exception.pid, p.pid)
        self.assertEqual(exc.exception.name, p.name())

    def test_cwd_zombie(self):
        with mock.patch("psutil._pslinux.os.readlink",
                        side_effect=OSError(errno.ENOENT, "")) as m:
            p = psutil.Process()
            p.name()
            with self.assertRaises(psutil.ZombieProcess) as exc:
                p.cwd()
            assert m.called
        self.assertEqual(exc.exception.pid, p.pid)
        self.assertEqual(exc.exception.name, p.name())

    def test_stat_file_parsing(self):
        from psutil._pslinux import CLOCK_TICKS

        args = [
            "0",      # pid
            "(cat)",  # name
            "Z",      # status
            "1",      # ppid
            "0",      # pgrp
            "0",      # session
            "0",      # tty
            "0",      # tpgid
            "0",      # flags
            "0",      # minflt
            "0",      # cminflt
            "0",      # majflt
            "0",      # cmajflt
            "2",      # utime
            "3",      # stime
            "4",      # cutime
            "5",      # cstime
            "0",      # priority
            "0",      # nice
            "0",      # num_threads
            "0",      # itrealvalue
            "6",      # starttime
            "0",      # vsize
            "0",      # rss
            "0",      # rsslim
            "0",      # startcode
            "0",      # endcode
            "0",      # startstack
            "0",      # kstkesp
            "0",      # kstkeip
            "0",      # signal
            "0",      # blocked
            "0",      # sigignore
            "0",      # sigcatch
            "0",      # wchan
            "0",      # nswap
            "0",      # cnswap
            "0",      # exit_signal
            "6",      # processor
            "0",      # rt priority
            "0",      # policy
            "7",      # delayacct_blkio_ticks
        ]
        content = " ".join(args).encode()
        with mock_open_content('/proc/%s/stat' % os.getpid(), content):
            p = psutil.Process()
            self.assertEqual(p.name(), 'cat')
            self.assertEqual(p.status(), psutil.STATUS_ZOMBIE)
            self.assertEqual(p.ppid(), 1)
            self.assertEqual(
                p.create_time(), 6 / CLOCK_TICKS + psutil.boot_time())
            cpu = p.cpu_times()
            self.assertEqual(cpu.user, 2 / CLOCK_TICKS)
            self.assertEqual(cpu.system, 3 / CLOCK_TICKS)
            self.assertEqual(cpu.children_user, 4 / CLOCK_TICKS)
            self.assertEqual(cpu.children_system, 5 / CLOCK_TICKS)
            self.assertEqual(cpu.iowait, 7 / CLOCK_TICKS)
            self.assertEqual(p.cpu_num(), 6)

    def test_status_file_parsing(self):
        with mock_open_content(
            '/proc/%s/status' % os.getpid(),
            textwrap.dedent("""\
                Uid:\t1000\t1001\t1002\t1003
                Gid:\t1004\t1005\t1006\t1007
                Threads:\t66
                Cpus_allowed:\tf
                Cpus_allowed_list:\t0-7
                voluntary_ctxt_switches:\t12
                nonvoluntary_ctxt_switches:\t13""").encode()):
            p = psutil.Process()
            self.assertEqual(p.num_ctx_switches().voluntary, 12)
            self.assertEqual(p.num_ctx_switches().involuntary, 13)
            self.assertEqual(p.num_threads(), 66)
            uids = p.uids()
            self.assertEqual(uids.real, 1000)
            self.assertEqual(uids.effective, 1001)
            self.assertEqual(uids.saved, 1002)
            gids = p.gids()
            self.assertEqual(gids.real, 1004)
            self.assertEqual(gids.effective, 1005)
            self.assertEqual(gids.saved, 1006)
            self.assertEqual(p._proc._get_eligible_cpus(), list(range(0, 8)))


@unittest.skipIf(not LINUX, "LINUX only")
class TestProcessAgainstStatus(PsutilTestCase):
    """/proc/pid/stat and /proc/pid/status have many values in common.
    Whenever possible, psutil uses /proc/pid/stat (it's faster).
    For all those cases we check that the value found in
    /proc/pid/stat (by psutil) matches the one found in
    /proc/pid/status.
    """

    @classmethod
    def setUpClass(cls):
        cls.proc = psutil.Process()

    def read_status_file(self, linestart):
        with psutil._psplatform.open_text(
                '/proc/%s/status' % self.proc.pid) as f:
            for line in f:
                line = line.strip()
                if line.startswith(linestart):
                    value = line.partition('\t')[2]
                    try:
                        return int(value)
                    except ValueError:
                        return value
            raise ValueError("can't find %r" % linestart)

    def test_name(self):
        value = self.read_status_file("Name:")
        self.assertEqual(self.proc.name(), value)

    def test_status(self):
        value = self.read_status_file("State:")
        value = value[value.find('(') + 1:value.rfind(')')]
        value = value.replace(' ', '-')
        self.assertEqual(self.proc.status(), value)

    def test_ppid(self):
        value = self.read_status_file("PPid:")
        self.assertEqual(self.proc.ppid(), value)

    def test_num_threads(self):
        value = self.read_status_file("Threads:")
        self.assertEqual(self.proc.num_threads(), value)

    def test_uids(self):
        value = self.read_status_file("Uid:")
        value = tuple(map(int, value.split()[1:4]))
        self.assertEqual(self.proc.uids(), value)

    def test_gids(self):
        value = self.read_status_file("Gid:")
        value = tuple(map(int, value.split()[1:4]))
        self.assertEqual(self.proc.gids(), value)

    @retry_on_failure()
    def test_num_ctx_switches(self):
        value = self.read_status_file("voluntary_ctxt_switches:")
        self.assertEqual(self.proc.num_ctx_switches().voluntary, value)
        value = self.read_status_file("nonvoluntary_ctxt_switches:")
        self.assertEqual(self.proc.num_ctx_switches().involuntary, value)

    def test_cpu_affinity(self):
        value = self.read_status_file("Cpus_allowed_list:")
        if '-' in str(value):
            min_, max_ = map(int, value.split('-'))
            self.assertEqual(
                self.proc.cpu_affinity(), list(range(min_, max_ + 1)))

    def test_cpu_affinity_eligible_cpus(self):
        value = self.read_status_file("Cpus_allowed_list:")
        with mock.patch("psutil._pslinux.per_cpu_times") as m:
            self.proc._proc._get_eligible_cpus()
        if '-' in str(value):
            assert not m.called
        else:
            assert m.called


# =====================================================================
# --- test utils
# =====================================================================


@unittest.skipIf(not LINUX, "LINUX only")
class TestUtils(PsutilTestCase):

    def test_readlink(self):
        with mock.patch("os.readlink", return_value="foo (deleted)") as m:
            self.assertEqual(psutil._psplatform.readlink("bar"), "foo")
            assert m.called

    def test_cat(self):
        testfn = self.get_testfn()
        with open(testfn, "wt") as f:
            f.write("foo ")
        self.assertEqual(psutil._psplatform.cat(testfn, binary=False), "foo")
        self.assertEqual(psutil._psplatform.cat(testfn, binary=True), b"foo")
        self.assertEqual(
            psutil._psplatform.cat(testfn + '??', fallback="bar"), "bar")


if __name__ == '__main__':
    from psutil.tests.runner import run_from_name
    run_from_name(__file__)