Merge remote-tracking branch 'origin/upstream-master'

am: 9b55afda07

Change-Id: I9f4a778e138589fcab2330147635e8d6c01c6e37

1 files changed, 719 insertions, 0 deletions

diff --git a/test/test_examples.py b/test/test_examples.py
new file mode 100755
index 0000000..5d6dacc
--- /dev/null
+++ b/test/test_examples.py
@@ -0,0 +1,719 @@
+#!/usr/bin/env python3
+
+if __name__ == '__main__':
+    import pytest
+    import sys
+    sys.exit(pytest.main([__file__] + sys.argv[1:]))
+
+import subprocess
+import os
+import sys
+import py
+import pytest
+import stat
+import shutil
+import filecmp
+import tempfile
+import time
+import errno
+import sys
+from tempfile import NamedTemporaryFile
+from contextlib import contextmanager
+from util import (wait_for_mount, umount, cleanup, base_cmdline,
+                  safe_sleep, basename, fuse_test_marker, test_printcap,
+                  fuse_proto, powerset)
+from os.path import join as pjoin
+
+pytestmark = fuse_test_marker()
+
+TEST_FILE = __file__
+
+with open(TEST_FILE, 'rb') as fh:
+    TEST_DATA = fh.read()
+
+def name_generator(__ctr=[0]):
+    __ctr[0] += 1
+    return 'testfile_%d' % __ctr[0]
+
+options = []
+if sys.platform == 'linux':
+    options.append('clone_fd')
+
+def invoke_directly(mnt_dir, name, options):
+    cmdline = base_cmdline + [ pjoin(basename, 'example', name),
+                               '-f', mnt_dir, '-o', ','.join(options) ]
+    if name == 'hello_ll':
+        # supports single-threading only
+        cmdline.append('-s')
+
+    return cmdline
+
+def invoke_mount_fuse(mnt_dir, name, options):
+    return base_cmdline + [ pjoin(basename, 'util', 'mount.fuse3'),
+                            name, mnt_dir, '-o', ','.join(options) ]
+
+def invoke_mount_fuse_drop_privileges(mnt_dir, name, options):
+    if os.getuid() != 0:
+        pytest.skip('drop_privileges requires root, skipping.')
+
+    return invoke_mount_fuse(mnt_dir, name, options + ('drop_privileges',))
+
+class raii_tmpdir:
+    def __init__(self):
+        self.d = tempfile.mkdtemp()
+
+    def __str__(self):
+        return str(self.d)
+
+    def mkdir(self, path):
+        return py.path.local(str(self.d)).mkdir(path)
+
+@pytest.fixture
+def short_tmpdir():
+    return raii_tmpdir()
+
+@pytest.mark.parametrize("cmdline_builder", (invoke_directly, invoke_mount_fuse,
+                                             invoke_mount_fuse_drop_privileges))
+@pytest.mark.parametrize("options", powerset(options))
+@pytest.mark.parametrize("name", ('hello', 'hello_ll'))
+def test_hello(tmpdir, name, options, cmdline_builder, output_checker):
+    mnt_dir = str(tmpdir)
+    mount_process = subprocess.Popen(
+        cmdline_builder(mnt_dir, name, options),
+        stdout=output_checker.fd, stderr=output_checker.fd)
+    try:
+        wait_for_mount(mount_process, mnt_dir)
+        assert os.listdir(mnt_dir) == [ 'hello' ]
+        filename = pjoin(mnt_dir, 'hello')
+        with open(filename, 'r') as fh:
+            assert fh.read() == 'Hello World!\n'
+        with pytest.raises(IOError) as exc_info:
+            open(filename, 'r+')
+        assert exc_info.value.errno == errno.EACCES
+        with pytest.raises(IOError) as exc_info:
+            open(filename + 'does-not-exist', 'r+')
+        assert exc_info.value.errno == errno.ENOENT
+    except:
+        cleanup(mount_process, mnt_dir)
+        raise
+    else:
+        umount(mount_process, mnt_dir)
+
+@pytest.mark.parametrize("writeback", (False, True))
+@pytest.mark.parametrize("name", ('passthrough', 'passthrough_fh', 'passthrough_ll'))
+@pytest.mark.parametrize("debug", (False, True))
+def test_passthrough(short_tmpdir, name, debug, output_checker, writeback):
+    # Avoid false positives from libfuse debug messages
+    if debug:
+        output_checker.register_output(r'^   unique: [0-9]+, error: -[0-9]+ .+$',
+                                       count=0)
+
+    # test_syscalls prints "No error" under FreeBSD
+    output_checker.register_output(r"^ \d\d \[[^\]]+ message: 'No error: 0'\]",
+                                   count=0)
+
+    mnt_dir = str(short_tmpdir.mkdir('mnt'))
+    src_dir = str(short_tmpdir.mkdir('src'))
+
+    cmdline = base_cmdline + \
+              [ pjoin(basename, 'example', name),
+                '-f', mnt_dir ]
+    if debug:
+        cmdline.append('-d')
+
+    if writeback:
+        if name != 'passthrough_ll':
+            pytest.skip('example does not support writeback caching')
+        cmdline.append('-o')
+        cmdline.append('writeback')
+        
+    mount_process = subprocess.Popen(cmdline, stdout=output_checker.fd,
+                                     stderr=output_checker.fd)
+    try:
+        wait_for_mount(mount_process, mnt_dir)
+        work_dir = mnt_dir + src_dir
+
+        tst_statvfs(work_dir)
+        tst_readdir(src_dir, work_dir)
+        tst_readdir_big(src_dir, work_dir)
+        tst_open_read(src_dir, work_dir)
+        tst_open_write(src_dir, work_dir)
+        tst_create(work_dir)
+        tst_passthrough(src_dir, work_dir)
+        tst_append(src_dir, work_dir)
+        tst_seek(src_dir, work_dir)
+        tst_mkdir(work_dir)
+        tst_rmdir(src_dir, work_dir)
+        tst_unlink(src_dir, work_dir)
+        tst_symlink(work_dir)
+        if os.getuid() == 0:
+            tst_chown(work_dir)
+
+        # Underlying fs may not have full nanosecond resolution
+        tst_utimens(work_dir, ns_tol=1000)
+
+        tst_link(work_dir)
+        tst_truncate_path(work_dir)
+        tst_truncate_fd(work_dir)
+        tst_open_unlink(work_dir)
+
+        syscall_test_cmd = [ os.path.join(basename, 'test', 'test_syscalls'),
+                             work_dir, ':' + src_dir ]
+        if writeback:
+            # When writeback caching is enabled, kernel has to open files for
+            # reading even when userspace opens with O_WDONLY. This fails if the
+            # filesystem process doesn't have special permission.
+            syscall_test_cmd.append('-53')
+        subprocess.check_call(syscall_test_cmd)
+    except:
+        cleanup(mount_process, mnt_dir)
+        raise
+    else:
+        umount(mount_process, mnt_dir)
+
+@pytest.mark.parametrize("cache", (False, True))
+def test_passthrough_hp(short_tmpdir, cache, output_checker):
+    mnt_dir = str(short_tmpdir.mkdir('mnt'))
+    src_dir = str(short_tmpdir.mkdir('src'))
+
+    cmdline = base_cmdline + \
+              [ pjoin(basename, 'example', 'passthrough_hp'),
+                src_dir, mnt_dir ]
+
+    if not cache:
+        cmdline.append('--nocache')
+        
+    mount_process = subprocess.Popen(cmdline, stdout=output_checker.fd,
+                                     stderr=output_checker.fd)
+    try:
+        wait_for_mount(mount_process, mnt_dir)
+
+        tst_statvfs(mnt_dir)
+        tst_readdir(src_dir, mnt_dir)
+        tst_readdir_big(src_dir, mnt_dir)
+        tst_open_read(src_dir, mnt_dir)
+        tst_open_write(src_dir, mnt_dir)
+        tst_create(mnt_dir)
+        if not cache:
+            tst_passthrough(src_dir, mnt_dir)
+        tst_append(src_dir, mnt_dir)
+        tst_seek(src_dir, mnt_dir)
+        tst_mkdir(mnt_dir)
+        tst_rmdir(src_dir, mnt_dir)
+        tst_unlink(src_dir, mnt_dir)
+        tst_symlink(mnt_dir)
+        if os.getuid() == 0:
+            tst_chown(mnt_dir)
+
+        # Underlying fs may not have full nanosecond resolution
+        tst_utimens(mnt_dir, ns_tol=1000)
+
+        tst_link(mnt_dir)
+        tst_truncate_path(mnt_dir)
+        tst_truncate_fd(mnt_dir)
+        tst_open_unlink(mnt_dir)
+
+        # test_syscalls assumes that changes in source directory
+        # will be reflected immediately in mountpoint, so we
+        # can't use it.
+        if not cache:
+            syscall_test_cmd = [ os.path.join(basename, 'test', 'test_syscalls'),
+                             mnt_dir, ':' + src_dir ]
+            subprocess.check_call(syscall_test_cmd)
+    except:
+        cleanup(mount_process, mnt_dir)
+        raise
+    else:
+        umount(mount_process, mnt_dir)
+
+        
+@pytest.mark.skipif(fuse_proto < (7,11),
+                    reason='not supported by running kernel')
+def test_ioctl(tmpdir, output_checker):
+    progname = pjoin(basename, 'example', 'ioctl')
+    if not os.path.exists(progname):
+        pytest.skip('%s not built' % os.path.basename(progname))
+    
+    mnt_dir = str(tmpdir)
+    testfile = pjoin(mnt_dir, 'fioc')
+    cmdline = base_cmdline + [progname, '-f', mnt_dir ]
+    mount_process = subprocess.Popen(cmdline, stdout=output_checker.fd,
+                                     stderr=output_checker.fd)
+    try:
+        wait_for_mount(mount_process, mnt_dir)
+
+        cmdline = base_cmdline + \
+                  [ pjoin(basename, 'example', 'ioctl_client'),
+                    testfile ]
+        assert subprocess.check_output(cmdline) == b'0\n'
+        with open(testfile, 'wb') as fh:
+            fh.write(b'foobar')
+        assert subprocess.check_output(cmdline) == b'6\n'
+        subprocess.check_call(cmdline + [ '3' ])
+        with open(testfile, 'rb') as fh:
+            assert fh.read()== b'foo'
+    except:
+        cleanup(mount_process, mnt_dir)
+        raise
+    else:
+        umount(mount_process, mnt_dir)
+
+def test_poll(tmpdir, output_checker):
+    mnt_dir = str(tmpdir)
+    cmdline = base_cmdline + [pjoin(basename, 'example', 'poll'),
+               '-f', mnt_dir ]
+    mount_process = subprocess.Popen(cmdline, stdout=output_checker.fd,
+                                     stderr=output_checker.fd)
+    try:
+        wait_for_mount(mount_process, mnt_dir)
+        cmdline = base_cmdline + \
+                  [ pjoin(basename, 'example', 'poll_client') ]
+        subprocess.check_call(cmdline, cwd=mnt_dir)
+    except:
+        cleanup(mount_process, mnt_dir)
+        raise
+    else:
+        umount(mount_process, mnt_dir)
+
+def test_null(tmpdir, output_checker):
+    progname = pjoin(basename, 'example', 'null')
+    if not os.path.exists(progname):
+        pytest.skip('%s not built' % os.path.basename(progname))
+    
+    mnt_file = str(tmpdir) + '/file'
+    with open(mnt_file, 'w') as fh:
+        fh.write('dummy')
+    cmdline = base_cmdline + [ progname, '-f', mnt_file ]
+    mount_process = subprocess.Popen(cmdline, stdout=output_checker.fd,
+                                     stderr=output_checker.fd)
+    def test_fn(name):
+        return os.stat(name).st_size > 4000
+    try:
+        wait_for_mount(mount_process, mnt_file, test_fn)
+        with open(mnt_file, 'rb') as fh:
+            assert fh.read(382) == b'\0' * 382
+        with open(mnt_file, 'wb') as fh:
+            fh.write(b'whatever')
+    except:
+        cleanup(mount_process, mnt_file)
+        raise
+    else:
+        umount(mount_process, mnt_file)
+
+
+@pytest.mark.skipif(fuse_proto < (7,12),
+                    reason='not supported by running kernel')
+@pytest.mark.parametrize("notify", (True, False))
+def test_notify_inval_entry(tmpdir, notify, output_checker):
+    mnt_dir = str(tmpdir)
+    cmdline = base_cmdline + \
+              [ pjoin(basename, 'example', 'notify_inval_entry'),
+                '-f', '--update-interval=1',
+                '--timeout=5', mnt_dir ]
+    if not notify:
+        cmdline.append('--no-notify')
+    mount_process = subprocess.Popen(cmdline, stdout=output_checker.fd,
+                                     stderr=output_checker.fd)
+    try:
+        wait_for_mount(mount_process, mnt_dir)
+        fname = pjoin(mnt_dir, os.listdir(mnt_dir)[0])
+        try:
+            os.stat(fname)
+        except FileNotFoundError:
+            # We may have hit a race condition and issued
+            # readdir just before the name changed
+            fname = pjoin(mnt_dir, os.listdir(mnt_dir)[0])
+            os.stat(fname)
+
+        safe_sleep(2)
+        if not notify:
+            os.stat(fname)
+            safe_sleep(5)
+        with pytest.raises(FileNotFoundError):
+            os.stat(fname)
+    except:
+        cleanup(mount_process, mnt_dir)
+        raise
+    else:
+        umount(mount_process, mnt_dir)
+
+@pytest.mark.skipif(os.getuid() != 0,
+                    reason='needs to run as root')
+def test_cuse(output_checker):
+
+    # Valgrind warns about unknown ioctls, that's ok
+    output_checker.register_output(r'^==([0-9]+).+unhandled ioctl.+\n'
+                                   r'==\1== \s{3}.+\n'
+                                   r'==\1== \s{3}.+$', count=0)
+
+    devname = 'cuse-test-%d' % os.getpid()
+    devpath = '/dev/%s' % devname
+    cmdline = base_cmdline + \
+              [ pjoin(basename, 'example', 'cuse'),
+                '-f', '--name=%s' % devname ]
+    mount_process = subprocess.Popen(cmdline, stdout=output_checker.fd,
+                                     stderr=output_checker.fd)
+
+    cmdline = base_cmdline + \
+              [ pjoin(basename, 'example', 'cuse_client'),
+                devpath ]
+    try:
+        wait_for_mount(mount_process, devpath,
+                       test_fn=os.path.exists)
+        assert subprocess.check_output(cmdline + ['s']) == b'0\n'
+        data = b'some test data'
+        off = 5
+        proc = subprocess.Popen(cmdline + [ 'w', str(len(data)), str(off) ],
+                                stdin=subprocess.PIPE)
+        proc.stdin.write(data)
+        proc.stdin.close()
+        assert proc.wait(timeout=10) == 0
+        size = str(off + len(data)).encode() + b'\n'
+        assert subprocess.check_output(cmdline + ['s']) == size
+        out = subprocess.check_output(
+            cmdline + [ 'r', str(off + len(data) + 2), '0' ])
+        assert out == (b'\0' * off) + data
+    finally:
+        mount_process.terminate()
+
+@contextmanager
+def os_open(name, flags):
+    fd = os.open(name, flags)
+    try:
+        yield fd
+    finally:
+        os.close(fd)
+
+def os_create(name):
+    os.close(os.open(name, os.O_CREAT | os.O_RDWR))
+
+def tst_unlink(src_dir, mnt_dir):
+    name = name_generator()
+    fullname = mnt_dir + "/" + name
+    with open(pjoin(src_dir, name), 'wb') as fh:
+        fh.write(b'hello')
+    assert name in os.listdir(mnt_dir)
+    os.unlink(fullname)
+    with pytest.raises(OSError) as exc_info:
+        os.stat(fullname)
+    assert exc_info.value.errno == errno.ENOENT
+    assert name not in os.listdir(mnt_dir)
+
+def tst_mkdir(mnt_dir):
+    dirname = name_generator()
+    fullname = mnt_dir + "/" + dirname
+    os.mkdir(fullname)
+    fstat = os.stat(fullname)
+    assert stat.S_ISDIR(fstat.st_mode)
+    assert os.listdir(fullname) ==  []
+    # Some filesystem (e.g. BTRFS) don't track st_nlink for directories
+    assert fstat.st_nlink in (1,2)
+    assert dirname in os.listdir(mnt_dir)
+
+def tst_rmdir(src_dir, mnt_dir):
+    name = name_generator()
+    fullname = mnt_dir + "/" + name
+    os.mkdir(pjoin(src_dir, name))
+    assert name in os.listdir(mnt_dir)
+    os.rmdir(fullname)
+    with pytest.raises(OSError) as exc_info:
+        os.stat(fullname)
+    assert exc_info.value.errno == errno.ENOENT
+    assert name not in os.listdir(mnt_dir)
+
+def tst_symlink(mnt_dir):
+    linkname = name_generator()
+    fullname = mnt_dir + "/" + linkname
+    os.symlink("/imaginary/dest", fullname)
+    fstat = os.lstat(fullname)
+    assert stat.S_ISLNK(fstat.st_mode)
+    assert os.readlink(fullname) == "/imaginary/dest"
+    assert fstat.st_nlink == 1
+    assert linkname in os.listdir(mnt_dir)
+
+def tst_create(mnt_dir):
+    name = name_generator()
+    fullname = pjoin(mnt_dir, name)
+    with pytest.raises(OSError) as exc_info:
+        os.stat(fullname)
+    assert exc_info.value.errno == errno.ENOENT
+    assert name not in os.listdir(mnt_dir)
+
+    fd = os.open(fullname, os.O_CREAT | os.O_RDWR)
+    os.close(fd)
+
+    assert name in os.listdir(mnt_dir)
+    fstat = os.lstat(fullname)
+    assert stat.S_ISREG(fstat.st_mode)
+    assert fstat.st_nlink == 1
+    assert fstat.st_size == 0
+
+def tst_chown(mnt_dir):
+    filename = pjoin(mnt_dir, name_generator())
+    os.mkdir(filename)
+    fstat = os.lstat(filename)
+    uid = fstat.st_uid
+    gid = fstat.st_gid
+
+    uid_new = uid + 1
+    os.chown(filename, uid_new, -1)
+    fstat = os.lstat(filename)
+    assert fstat.st_uid == uid_new
+    assert fstat.st_gid == gid
+
+    gid_new = gid + 1
+    os.chown(filename, -1, gid_new)
+    fstat = os.lstat(filename)
+    assert fstat.st_uid == uid_new
+    assert fstat.st_gid == gid_new
+
+def tst_open_read(src_dir, mnt_dir):
+    name = name_generator()
+    with open(pjoin(src_dir, name), 'wb') as fh_out, \
+         open(TEST_FILE, 'rb') as fh_in:
+        shutil.copyfileobj(fh_in, fh_out)
+
+    assert filecmp.cmp(pjoin(mnt_dir, name), TEST_FILE, False)
+
+def tst_open_write(src_dir, mnt_dir):
+    name = name_generator()
+    os_create(pjoin(src_dir, name))
+    fullname = pjoin(mnt_dir, name)
+    with open(fullname, 'wb') as fh_out, \
+         open(TEST_FILE, 'rb') as fh_in:
+        shutil.copyfileobj(fh_in, fh_out)
+
+    assert filecmp.cmp(fullname, TEST_FILE, False)
+
+def tst_append(src_dir, mnt_dir):
+    name = name_generator()
+    os_create(pjoin(src_dir, name))
+    fullname = pjoin(mnt_dir, name)
+    with os_open(fullname, os.O_WRONLY) as fd:
+        os.write(fd, b'foo\n')
+    with os_open(fullname, os.O_WRONLY|os.O_APPEND) as fd:
+        os.write(fd, b'bar\n')
+
+    with open(fullname, 'rb') as fh:
+        assert fh.read() == b'foo\nbar\n'
+
+def tst_seek(src_dir, mnt_dir):
+    name = name_generator()
+    os_create(pjoin(src_dir, name))
+    fullname = pjoin(mnt_dir, name)
+    with os_open(fullname, os.O_WRONLY) as fd:
+        os.lseek(fd, 1, os.SEEK_SET)
+        os.write(fd, b'foobar\n')
+    with os_open(fullname, os.O_WRONLY) as fd:
+        os.lseek(fd, 4, os.SEEK_SET)
+        os.write(fd, b'com')
+        
+    with open(fullname, 'rb') as fh:
+        assert fh.read() == b'\0foocom\n'
+        
+def tst_open_unlink(mnt_dir):
+    name = pjoin(mnt_dir, name_generator())
+    data1 = b'foo'
+    data2 = b'bar'
+    fullname = pjoin(mnt_dir, name)
+    with open(fullname, 'wb+', buffering=0) as fh:
+        fh.write(data1)
+        os.unlink(fullname)
+        with pytest.raises(OSError) as exc_info:
+            os.stat(fullname)
+        assert exc_info.value.errno == errno.ENOENT
+        assert name not in os.listdir(mnt_dir)
+        fh.write(data2)
+        fh.seek(0)
+        assert fh.read() == data1+data2
+
+def tst_statvfs(mnt_dir):
+    os.statvfs(mnt_dir)
+
+def tst_link(mnt_dir):
+    name1 = pjoin(mnt_dir, name_generator())
+    name2 = pjoin(mnt_dir, name_generator())
+    shutil.copyfile(TEST_FILE, name1)
+    assert filecmp.cmp(name1, TEST_FILE, False)
+
+    fstat1 = os.lstat(name1)
+    assert fstat1.st_nlink == 1
+
+    os.link(name1, name2)
+
+    fstat1 = os.lstat(name1)
+    fstat2 = os.lstat(name2)
+    assert fstat1 == fstat2
+    assert fstat1.st_nlink == 2
+    assert os.path.basename(name2) in os.listdir(mnt_dir)
+    assert filecmp.cmp(name1, name2, False)
+
+    # Since RELEASE requests are asynchronous, it is possible that
+    # libfuse still considers the file to be open at this point
+    # and (since -o hard_remove is not used) renames it instead of
+    # deleting it. In that case, the following lstat() call will
+    # still report an st_nlink value of 2 (cf. issue #157).
+    os.unlink(name2)
+
+    assert os.path.basename(name2) not in os.listdir(mnt_dir)
+    with pytest.raises(FileNotFoundError):
+        os.lstat(name2)
+
+    # See above, we may have to wait until RELEASE has been
+    # received before the st_nlink value is correct.
+    maxwait = time.time() + 2
+    fstat1 = os.lstat(name1)
+    while fstat1.st_nlink == 2 and time.time() < maxwait:
+        fstat1 = os.lstat(name1)
+        time.sleep(0.1)
+    assert fstat1.st_nlink == 1
+
+    os.unlink(name1)
+
+def tst_readdir(src_dir, mnt_dir):
+    newdir = name_generator()
+
+    src_newdir = pjoin(src_dir, newdir)
+    mnt_newdir = pjoin(mnt_dir, newdir)
+    file_ = src_newdir + "/" + name_generator()
+    subdir = src_newdir + "/" + name_generator()
+    subfile = subdir + "/" + name_generator()
+
+    os.mkdir(src_newdir)
+    shutil.copyfile(TEST_FILE, file_)
+    os.mkdir(subdir)
+    shutil.copyfile(TEST_FILE, subfile)
+
+    listdir_is = os.listdir(mnt_newdir)
+    listdir_is.sort()
+    listdir_should = [ os.path.basename(file_), os.path.basename(subdir) ]
+    listdir_should.sort()
+    assert listdir_is == listdir_should
+
+    os.unlink(file_)
+    os.unlink(subfile)
+    os.rmdir(subdir)
+    os.rmdir(src_newdir)
+
+def tst_readdir_big(src_dir, mnt_dir):
+
+    # Add enough entries so that readdir needs to be called
+    # multiple times.
+    fnames = []
+    for i in range(500):
+        fname  = ('A rather long filename to make sure that we '
+                  'fill up the buffer - ' * 3) + str(i)
+        with open(pjoin(src_dir, fname), 'w') as fh:
+            fh.write('File %d' % i)
+        fnames.append(fname)
+
+    listdir_is = sorted(os.listdir(mnt_dir))
+    listdir_should = sorted(os.listdir(src_dir))
+    assert listdir_is == listdir_should
+
+    for fname in fnames:
+        stat_src = os.stat(pjoin(src_dir, fname))
+        stat_mnt = os.stat(pjoin(mnt_dir, fname))
+        assert stat_src.st_ino == stat_mnt.st_ino
+        assert stat_src.st_mtime == stat_mnt.st_mtime
+        assert stat_src.st_ctime == stat_mnt.st_ctime
+        assert stat_src.st_size == stat_mnt.st_size
+        os.unlink(pjoin(src_dir, fname))
+    
+def tst_truncate_path(mnt_dir):
+    assert len(TEST_DATA) > 1024
+
+    filename = pjoin(mnt_dir, name_generator())
+    with open(filename, 'wb') as fh:
+        fh.write(TEST_DATA)
+
+    fstat = os.stat(filename)
+    size = fstat.st_size
+    assert size == len(TEST_DATA)
+
+    # Add zeros at the end
+    os.truncate(filename, size + 1024)
+    assert os.stat(filename).st_size == size + 1024
+    with open(filename, 'rb') as fh:
+        assert fh.read(size) == TEST_DATA
+        assert fh.read(1025) == b'\0' * 1024
+
+    # Truncate data
+    os.truncate(filename, size - 1024)
+    assert os.stat(filename).st_size == size - 1024
+    with open(filename, 'rb') as fh:
+        assert fh.read(size) == TEST_DATA[:size-1024]
+
+    os.unlink(filename)
+
+def tst_truncate_fd(mnt_dir):
+    assert len(TEST_DATA) > 1024
+    with NamedTemporaryFile('w+b', 0, dir=mnt_dir) as fh:
+        fd = fh.fileno()
+        fh.write(TEST_DATA)
+        fstat = os.fstat(fd)
+        size = fstat.st_size
+        assert size == len(TEST_DATA)
+
+        # Add zeros at the end
+        os.ftruncate(fd, size + 1024)
+        assert os.fstat(fd).st_size == size + 1024
+        fh.seek(0)
+        assert fh.read(size) == TEST_DATA
+        assert fh.read(1025) == b'\0' * 1024
+
+        # Truncate data
+        os.ftruncate(fd, size - 1024)
+        assert os.fstat(fd).st_size == size - 1024
+        fh.seek(0)
+        assert fh.read(size) == TEST_DATA[:size-1024]
+
+def tst_utimens(mnt_dir, ns_tol=0):
+    filename = pjoin(mnt_dir, name_generator())
+    os.mkdir(filename)
+    fstat = os.lstat(filename)
+
+    atime = fstat.st_atime + 42.28
+    mtime = fstat.st_mtime - 42.23
+    if sys.version_info < (3,3):
+        os.utime(filename, (atime, mtime))
+    else:
+        atime_ns = fstat.st_atime_ns + int(42.28*1e9)
+        mtime_ns = fstat.st_mtime_ns - int(42.23*1e9)
+        os.utime(filename, None, ns=(atime_ns, mtime_ns))
+
+    fstat = os.lstat(filename)
+
+    assert abs(fstat.st_atime - atime) < 1
+    assert abs(fstat.st_mtime - mtime) < 1
+    if sys.version_info >= (3,3):
+        assert abs(fstat.st_atime_ns - atime_ns) <= ns_tol
+        assert abs(fstat.st_mtime_ns - mtime_ns) <= ns_tol
+
+def tst_passthrough(src_dir, mnt_dir):
+    name = name_generator()
+    src_name = pjoin(src_dir, name)
+    mnt_name = pjoin(src_dir, name)
+    assert name not in os.listdir(src_dir)
+    assert name not in os.listdir(mnt_dir)
+    with open(src_name, 'w') as fh:
+        fh.write('Hello, world')
+    assert name in os.listdir(src_dir)
+    assert name in os.listdir(mnt_dir)
+    assert os.stat(src_name) == os.stat(mnt_name)
+
+    name = name_generator()
+    src_name = pjoin(src_dir, name)
+    mnt_name = pjoin(src_dir, name)
+    assert name not in os.listdir(src_dir)
+    assert name not in os.listdir(mnt_dir)
+    with open(mnt_name, 'w') as fh:
+        fh.write('Hello, world')
+    assert name in os.listdir(src_dir)
+    assert name in os.listdir(mnt_dir)
+    assert os.stat(src_name) == os.stat(mnt_name)
+
+# avoid warning about unused import
+test_printcap
+
+