def test_iterator_buffering(tmppath):
"Test file iteration."
f = "data/multiline.txt"
xfile = XRootDFile(mkurl(join(tmppath, f)), 'r')
assert len(list(iter(xfile))) == len(open(join(tmppath, f)).readlines())
xfile = XRootDFile(mkurl(join(tmppath, f)), 'r', buffering=10)
assert len(list(iter(xfile))) == int(math.ceil(xfile.size / 10.0))
def test_writelines(tmppath):
"""Test writelines()."""
xfile = XRootDFile(mkurl(join(tmppath, "data/multiline.txt")), 'r')
yfile = XRootDFile(mkurl(join(tmppath, "data/newfile.txt")), 'w+')
yfile.writelines(xfile.xreadlines())
xfile.seek(0), yfile.seek(0)
assert xfile.readlines() == yfile.readlines()
def test__is_open(tmppath):
"""Test _is_open()"""
fd = get_tsta_file(tmppath)
full_path = fd['full_path']
xfile = XRootDFile(mkurl(full_path))
assert not xfile.closed
xfile.close()
assert xfile.closed
def test_open_close(tmppath):
"""Test close() on an open file."""
fd = get_tsta_file(tmppath)
full_path = fd['full_path']
xfile = XRootDFile(mkurl(full_path))
assert xfile
assert not xfile.closed
xfile.close()
assert xfile.closed
def test_read_binary(tmppath):
"""Tests reading binary data from an existing file."""
fd = get_bin_testfile(tmppath)
fb = get_copy_file(fd, binary=True)
fp, fc = fd['full_path'], fd['contents']
fp2 = fb['full_path']
pfile = open(fp2, 'rb')
xfile = XRootDFile(mkurl(fp), 'rb')
assert xfile.read() == pfile.read() == fc
def test_seekable(tmppath):
"""Test seekable."""
assert XRootDFile(
mkurl(join(tmppath, "data/testa.txt")), 'r-').seekable() is False
assert XRootDFile(
mkurl(join(tmppath, "data/testa.txt")), 'r').seekable() is True
assert XRootDFile(
mkurl(join(tmppath, "data/testa.txt")), 'w').seekable() is True
assert XRootDFile(
mkurl(join(tmppath, "data/testa.txt")), 'w-').seekable() is False
assert XRootDFile(
mkurl(join(tmppath, "data/testa.txt")), 'r+').seekable() is True
def test_init_readmode_basic(tmppath):
# Non-existing file causes what?
# Resource not found error.
fn, fp, fc = 'nope', 'data/', ''
full_path = join(tmppath, fp, fn)
pytest.raises(ResourceNotFoundError, XRootDFile, mkurl(full_path),
mode='r')
# Existing file can be read?
fd = get_tsta_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path), mode='r')
assert xfile
assert xfile.read() == fc
def test_read_existing(tmppath):
"""Test read() on an existing non-empty file."""
fd = get_tsta_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path))
res = xfile.read()
assert res == fc
# After having read the entire file, the file pointer is at the
# end of the file and consecutive reads return the empty string.
assert xfile.read() == ''
# reset ipp to start
xfile.seek(0)
assert xfile.read(1) == fc[0]
assert xfile.read(2) == fc[1:3]
overflow_read = xfile.read(len(fc))
assert overflow_read == fc[3:]
# Mock an error, yayy!
fake_status = {
"status": 3,
"code": 0,
"ok": False,
"errno": errno.EREMOTE,
"error": True,
"message": '[FATAL] Remote I/O Error',
"fatal": True,
"shellcode": 51
}
xfile._file.read = Mock(return_value=(XRootDStatus(fake_status), None))
pytest.raises(IOError, xfile.read)
def test_truncate3(tmppath):
"""Test truncate(0 < size < self._size)."""
fd = get_mltl_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path), 'r+')
initcp = xfile.tell()
newsiz = len(fc)//2
xfile.truncate(newsiz)
assert xfile.tell() == initcp
xfile.seek(0) # reset the internal pointer before reading
assert xfile.read() == fc[:newsiz]
def test_truncate2(tmppath):
"""Test truncate(self._size)."""
fd = get_tsta_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path), 'r+')
conts = xfile.read()
assert conts == fc
newsize = xfile.size
xfile.truncate(newsize)
assert xfile.tell() == newsize
assert xfile.size == len(fc)
xfile.seek(0)
assert xfile.read() == conts
def test_init_newline(tmppath):
"""Tests fs.open() with specified newline parameter."""
fd = get_tsta_file(tmppath)
fp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fp))
assert xfile._newline == '\n'
xfile.close()
xfile = XRootDFile(mkurl(fp), newline='\n')
assert xfile._newline == '\n'
xfile.close()
pytest.raises(UnsupportedError, XRootDFile, mkurl(fp), mode='r',
newline='what')
def test_size(tmppath):
"""Tests for the size property size."""
fd = get_tsta_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path))
assert xfile.size == len(fc)
# Length of empty file
xfile = XRootDFile(mkurl(join(tmppath, fd['dir'], 'whut')), 'w+')
assert xfile.size == len('')
# Length of multiline file
fd = get_mltl_file(tmppath)
fpp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fpp))
assert xfile.size == len(fc)
# Mock the error
fake_status = {
"status": 3,
"code": 0,
"ok": False,
"errno": errno.EREMOTE,
"error": True,
"message": '[FATAL] Remote I/O Error',
"fatal": True,
"shellcode": 51
}
xfile.close()
xfile = XRootDFile(mkurl(full_path))
xfile._file.stat = Mock(return_value=(XRootDStatus(fake_status), None))
try:
xfile.size
assert False
except IOError:
assert True
def test_init_basic(tmppath):
"""Test basic initialization of existing file."""
fname = 'testa.txt'
fpath = 'data/'
fcontents = 'testa.txt\n'
full_fpath = join(tmppath, fpath, fname)
xfile = XRootDFile(mkurl(full_fpath))
assert xfile
assert type(xfile == XRootDFile)
assert xfile._file
assert xfile.mode == 'r'
# Verify that underlying/wrapped file can be read.
statmsg, res = xfile._file.read()
assert res == fcontents
def test_truncate4(tmppath):
"""Verifies that truncate() raises errors on non-truncatable files."""
fd = get_mltl_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path), 'r')
pytest.raises(IOError, xfile.truncate, 0)
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'w-')
pytest.raises(IOError, xfile.truncate, 0)
def test_xreadlines(tmppath):
"""Tests xreadlines()"""
fp = get_mltl_file(tmppath)['full_path']
xfile = XRootDFile(mkurl(fp), 'r')
rl = xfile.readlines()
xfile.seek(0)
xl = xfile.xreadlines()
assert xl != rl
assert list(xl) == rl
def test_init_writemode_basic(tmppath):
# Non-existing file is created.
fn, fp, fc = 'nope', 'data/', ''
full_path = join(tmppath, fp, fn)
xfile = XRootDFile(mkurl(full_path), mode='w+')
assert xfile
assert xfile.read() == fc
# Existing file is truncated
fd = get_tsta_file(tmppath)
full_path = fd['full_path']
xfile = XRootDFile(mkurl(full_path), mode='w+')
assert xfile
assert xfile.read() == ''
assert xfile.size == 0
assert xfile.tell() == 0
def test_tell_after_open(tmppath):
"""Tests for tell's init values in the various file modes."""
fd = get_tsta_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path), 'r')
assert xfile.tell() == 0
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'r+')
assert xfile.tell() == 0
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'r-')
assert xfile.tell() == 0
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'a')
assert xfile.tell() == len(fc)
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'a+')
assert xfile.tell() == len(fc)
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'w')
assert xfile.tell() == 0
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'w-')
assert xfile.tell() == 0
xfile.close()
def test_write_binary(tmppath):
"""Tests for writing binary data to file."""
fd = get_bin_testfile(tmppath)
fp, fc = fd['full_path'], fd['contents']
# Test w/ confirmed binary data read from a binary file
xf_new = XRootDFile(mkurl(join(tmppath, 'data/tmp_bin')), 'wb+')
xf_new.write(fc), xf_new.seek(0)
assert xf_new.read() == fc
xf_new.close()
# Verify persistence.
xf_new = XRootDFile(mkurl(join(tmppath, 'data/tmp_bin')), 'r+')
assert xf_new.read() == fc
# Test truncate
xf_new.truncate()
xf_new.seek(0)
assert xf_new.read() == fc
xf_new.close()
# Test with bytearray
xf_new = XRootDFile(mkurl(join(tmppath, 'data/tmp_bin')), 'wb+')
barr = bytearray(range(0, 5))
xf_new.write(barr), xf_new.seek(0)
assert xf_new.read() == barr
xf_new.close()
# Verify persistence.
xf_new = XRootDFile(mkurl(join(tmppath, 'data/tmp_bin')), 'r')
assert xf_new.read() == barr
xf_new.close()
def test_write_and_read(tmppath):
"""Tests that the XRootDFile behaves like a regular python file in w+."""
fd = get_tsta_file(tmppath)
fb = get_copy_file(fd)
fp, fc = fd['full_path'], fd['contents']
fp2 = fb['full_path']
writestr = "Hello fair mare what fine stairs."
seekpoint = len(writestr)//2
# In 'w' (and variant modes) the file's contents are deleted upon opening.
pfile = open(fp2, 'w+')
xfile = XRootDFile(mkurl(fp), 'w+')
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
assert xfile.tell() == pfile.tell()
xfile.write(writestr), pfile.write(writestr)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
xfile.seek(0), pfile.seek(0)
assert xfile.read() == pfile.read()
assert xfile.tell() == pfile.tell()
xfile.seek(seekpoint), pfile.seek(seekpoint)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
assert xfile.tell() == pfile.tell()
def test_seek_past_eof_wr(tmppath):
"""Tests read/write/truncate behaviour after seeking past the EOF, 'w+'"""
fd = get_tsta_file(tmppath)
fb = get_copy_file(fd)
fp, fc = fd['full_path'], u''
fp2 = fb['full_path']
wstr = "www"
eof = len(fc)
skpnt = len(fc)+4
pfile = open(fp2, 'w+')
xfile = XRootDFile(mkurl(fp), 'w+')
xfile.seek(skpnt), pfile.seek(skpnt)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
assert xfile.tell() == pfile.tell()
assert xfile.tell() == skpnt
xfile.write(wstr), pfile.write(wstr)
assert xfile.tell() == pfile.tell()
xfile.seek(eof), pfile.seek(eof)
assert xfile.read() == pfile.read() == '\x00'*(skpnt-eof) + wstr
assert xfile.tell() == pfile.tell()
xfile.seek(0), pfile.seek(0)
assert xfile.read() == pfile.read()
xfile.truncate(skpnt), pfile.truncate(skpnt)
assert xfile.tell() == pfile.tell() == skpnt + len(wstr)
xfile.write(wstr), pfile.write(wstr)
expected = fc + '\x00'*(skpnt-eof+len(wstr)) + wstr
xfile.seek(0), pfile.seek(0)
assert xfile.read() == pfile.read() == expected
def test_read_errors(tmppath):
fd = get_tsta_file(tmppath)
fp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fp), 'r')
xfile.close()
pytest.raises(ValueError, xfile.read)
def test_read_and_write(tmppath):
"""Tests that the XRDFile behaves like a regular python file."""
fd = get_tsta_file(tmppath)
fb = get_copy_file(fd)
fp, fc = fd['full_path'], fd['contents']
fp2 = fb['full_path']
seekpoint = len(fc)//2
writestr = "Come what may in May this day says Ray all gay like Jay"
pfile = open(fp2, 'r+')
xfile = XRootDFile(mkurl(fp), 'r+')
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
assert xfile.tell() == pfile.tell()
xfile.seek(seekpoint), pfile.seek(seekpoint)
assert xfile.tell() == pfile.tell()
xfile.write(writestr), pfile.write(writestr)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
xfile.seek(0), pfile.seek(0)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
def test_init_streammodes(tmppath):
fd = get_tsta_file(tmppath)
fp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fp), 'r-')
pytest.raises(IOError, xfile.seek, 3)
assert xfile.size == len(fc)
assert xfile.tell() == 0
assert xfile.read() == fc
assert xfile.tell() == len(fc)
xfile.close()
xfile = XRootDFile(mkurl(fp), 'w-')
pytest.raises(IOError, xfile.read)
pytest.raises(IOError, xfile.seek, 3)
assert xfile.tell() == 0
assert xfile.size == 0
conts = 'hugs are delightful'
xfile.write(conts)
assert xfile.tell() == len(conts)
xfile.close()
xfile = XRootDFile(mkurl(fp), 'r')
assert xfile.read() == conts
def test_truncate1(tmppath):
"""Test truncate(0)."""
fd = get_tsta_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path), 'r+')
# r+ opens for r/w, and won't truncate the file automatically.
assert xfile.read() == fc
assert xfile.tell() == len(fc)
xfile.seek(0) # Reset ipp.
assert xfile.tell() == 0
# Truncate it to size 0.
xfile.truncate(0)
assert xfile.size == 0
assert xfile.tell() == 0
assert xfile.read() == ''
assert xfile.tell() == 0
xfile.close()
# Re-open same file.
xfile = XRootDFile(mkurl(full_path), 'r+')
assert xfile.size == 0
assert xfile.read() == ''
# Truncate it again!
xfile.truncate(0)
assert xfile.size == 0
assert xfile.read() == ''
# Truncate it twice.
xfile.truncate(0)
assert xfile.size == 0
assert xfile.read() == ''
# Truncate to 1.
xfile.truncate(1)
assert xfile.tell() == 0
assert xfile.size == 1
xfile.seek(0)
assert xfile.read() == '\x00'
assert xfile.tell() == 1
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'r+')
assert xfile.size == 1
assert xfile.read() == '\x00'
# Mock it.
fake_status = {
"status": 3,
"code": 0,
"ok": False,
"errno": errno.EREMOTE,
"error": True,
"message": '[FATAL] Remote I/O Error',
"fatal": True,
"shellcode": 51
}
xfile._file.truncate = Mock(return_value=(XRootDStatus(fake_status), None))
pytest.raises(IOError, xfile.truncate, 0)
def test_truncate5(tmppath):
"""Test truncate() (no arg)."""
fd = get_tsta_file(tmppath)
fb = get_copy_file(fd)
fp, fc = fd['full_path'], fd['contents']
fp2 = fb['full_path']
xfa = XRootDFile(mkurl(fp), 'r+')
xfb = XRootDFile(mkurl(fp2), 'r+')
acnts = xfa.read()
assert acnts == xfb.read()
# internal pointer starts at 0 in all 'r' modes.
xtell = xfa.tell()
assert xfa.tell() == xfb.tell()
# f.truncate() and f.truncate(self.tell()) should be equivalent
xfa.truncate(), xfb.truncate(xfb.tell())
assert xfa.size == xfb.size
assert xfa.tell() == xtell
assert xfb.tell() == xtell
assert xfb.read() == u''
assert xfa.read() == u''
xfa.seek(0), xfb.seek(0)
are = xfa.read()
assert are == fc
assert are == xfb.read()
def test_init_writemode(tmppath):
"""Tests for opening files in 'w(+)'"""
fd = get_tsta_file(tmppath)
fp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fp), 'w')
pytest.raises(IOError, xfile.read)
xfile.seek(1)
conts = 'what'
xfile.write(conts)
assert xfile.tell() == 1 + len(conts)
assert xfile.size == 1 + len(conts)
xfile.close()
xfile = XRootDFile(mkurl(fp), 'r')
fc = xfile.read()
assert fc == '\x00'+conts
assert not fc == conts
def test_init_appendread(tmppath):
"""Test for files opened in mode 'a+'."""
fd = get_tsta_file(tmppath)
fp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fp), 'a+')
assert xfile.mode == 'a+'
assert xfile.tell() == len(fc)
assert xfile.read() == u''
# Seeking is allowed, but writes still go on the end.
xfile.seek(0)
assert xfile.tell() == 0
newcont = u'butterflies'
xfile.write(newcont)
assert xfile.tell() == len(fc) + len(newcont)
xfile.seek(0)
assert xfile.read() == fc + newcont
xfile.write(fc)
xfile.seek(0)
xfile.read() == fc + newcont + fc
def test_init_append(tmppath):
"""Test for files opened 'a'"""
fd = get_tsta_file(tmppath)
fp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fp), 'a')
assert xfile.mode == 'a'
pytest.raises(IOError, xfile.read)
assert xfile.tell() == len(fc)
# Seeking is allowed, but writes still go on the end.
xfile.seek(0)
assert xfile.tell() == 0
newcont = u'butterflies'
xfile.write(newcont)
assert xfile.tell() == len(fc) + len(newcont)
# Can't read in this mode.
xfile.close()
xfile = XRootDFile(mkurl(fp), 'r')
assert xfile.read() == fc + newcont
xfile.close()
xfile = XRootDFile(mkurl(fp), 'a')
xfile.write(fc)
xfile.seek(0)
pytest.raises(IOError, xfile.read)
def test_readwrite_unicode(tmppath):
"""Test read/write unicode."""
if sys.getdefaultencoding() != 'ascii':
# Python 2 only problem
raise AssertionError(
"Default system encoding is not ascii. This is likely due to some"
" imported module changing it using sys.setdefaultencoding."
)
fd = get_tsta_file(tmppath)
fb = get_copy_file(fd)
fp, dummy = fd['full_path'], fd['contents']
fp2 = fb['full_path']
unicodestr = u"æøå"
pfile = open(fp2, 'w')
xfile = XRootDFile(mkurl(fp), 'w')
pytest.raises(UnicodeEncodeError, pfile.write, unicodestr)
pytest.raises(UnicodeEncodeError, xfile.write, unicodestr)
xfile.close()
xfile = XRootDFile(mkurl(fp), 'w+', encoding='utf-8')
xfile.write(unicodestr)
xfile.flush()
xfile.seek(0)
assert unicodestr.encode('utf8') == xfile.read()
xfile.close()
xfile = XRootDFile(mkurl(fp), 'w+', errors='ignore')
xfile.write(unicodestr)
xfile.flush()
xfile.seek(0)
assert unicodestr.encode('ascii', 'ignore') == xfile.read()
xfile.close()
def test_write(tmppath):
"""Test write()."""
# With a new file.
xfile = XRootDFile(mkurl(join(tmppath, 'data/nuts')), 'w+')
assert xfile.size == 0
conts = xfile.read()
assert not conts
nconts = 'Write.'
xfile.write(nconts)
assert xfile.tell() == len(nconts)
assert not xfile.closed
xfile.seek(0)
assert xfile.size == len(nconts)
assert xfile.read() == nconts
xfile.close()
# Verify persistence after closing.
xfile = XRootDFile(mkurl(join(tmppath, 'data/nuts')), 'r+')
assert xfile.size == len(nconts)
assert xfile.read() == nconts
# Seek(x>0) followed by a write
nc2 = 'hello'
cntr = len(nconts)//2
xfile.seek(cntr)
xfile.write(nc2)
assert xfile.tell() == len(nc2) + cntr
xfile.seek(0)
assert xfile.read() == nconts[:cntr] + nc2
xfile.close()
# Seek(x>0) followed by a write of len < size-x
fd = get_tsta_file(tmppath)
fp, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(fp), 'r+')
assert xfile.read() == fc
xfile.seek(2)
nc = 'yo'
xfile.write(nc)
assert xfile.tell() == len(nc) + 2
assert xfile.read() == fc[2+len(nc):]
# run w/ flushing == true
xfile.write('', True)
# Mock an error, yayy!
fake_status = {
"status": 3,
"code": 0,
"ok": False,
"errno": errno.EREMOTE,
"error": True,
"message": '[FATAL] Remote I/O Error',
"fatal": True,
"shellcode": 51
}
xfile._file.write = Mock(return_value=(XRootDStatus(fake_status), None))
pytest.raises(IOError, xfile.write, '')
def test_readline(tmppath):
"""Tests for readline()."""
fd = get_mltl_file(tmppath)
fb = get_copy_file(fd)
fp, fc = fd['full_path'], fd['contents']
fp2 = fb['full_path']
xfile, pfile = XRootDFile(mkurl(fp), 'r'), opener.open(fp2, 'r')
assert xfile.readline() == pfile.readline()
assert xfile.readline() == pfile.readline()
assert xfile.readline() == pfile.readline()
xfile.close(), pfile.close()
xfile, pfile = XRootDFile(mkurl(fp), 'r'), opener.open(fp2, 'r')
assert xfile.readline() == pfile.readline()
xfile.seek(0), pfile.seek(0)
assert xfile.readline() == pfile.readline()
assert xfile.tell(), pfile.tell()
xfile.close(), pfile.close()
xfile = XRootDFile(mkurl(fp), 'w+')
str1 = 'hello\n'
str2 = 'bye\n'
xfile.write(str1+str2)
xfile.seek(0)
assert xfile.readline() == str1
assert xfile.readline() == str2
assert xfile.readline() == ''
assert xfile.readline() == ''
xfile.seek(100)
assert xfile.readline() == ''
xfile.close()
xfile = XRootDFile(mkurl(fp), 'w+')
xfile.write(str2)
xfile.seek(len(str2)+1)
xfile.write(str2)
xfile.seek(0)
assert xfile.readline() == str2
assert xfile.readline() == u'\x00'+str2
def test_flush(tmppath):
"""Tests for flush()"""
# Mostly it just ensures calling it doesn't crash the program.
fd = get_tsta_file(tmppath)
full_path, fc = fd['full_path'], fd['contents']
xfile = XRootDFile(mkurl(full_path), 'w')
writestr = 'whut'
xfile.flush()
xfile.seek(0, SEEK_END)
xfile.write(writestr)
xfile.flush()
xfile.close()
xfile = XRootDFile(mkurl(full_path), 'r')
assert xfile.read() == writestr
# Fake/mock an error response
fake_status = {
"status": 3,
"code": 0,
"ok": False,
"errno": errno.EREMOTE,
"error": True,
"message": '[FATAL] Remote I/O Error',
"fatal": True,
"shellcode": 51
}
# Assign mock return value to the file's sync() function
# (which is called by flush())
xfile._file.sync = Mock(return_value=(XRootDStatus(fake_status), None))
pytest.raises(IOError, xfile.flush)
def test_truncate_read_write2(tmppath):
"""Tests behaviour of writing after seek(0) after
reading after truncating."""
fd = get_tsta_file(tmppath)
fb = get_copy_file(fd)
fp, fc = fd['full_path'], fd['contents']
fp2 = fb['full_path']
sp = len(fc)//2
wstr = "I am the string"
pfile = open(fp2, 'r+')
xfile = XRootDFile(mkurl(fp), 'r+')
xfile.truncate(sp), pfile.truncate(sp)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
assert xfile.tell() == pfile.tell()
xfile.seek(0), pfile.seek(0)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
xfile.seek(0), pfile.seek(0)
xfile.write(wstr), pfile.write(wstr)
assert xfile.tell() == pfile.tell()
assert xfile.read() == pfile.read()
xfile.seek(0), pfile.seek(0)
assert xfile.read() == pfile.read()
