def test_truncate():
s = u"1234567890"
sio = StringIO(s)
raises(ValueError, sio.truncate, -1)
sio.seek(6)
res = sio.truncate()
assert res == 6
assert sio.getvalue() == s[:6]
res = sio.truncate(4)
assert res == 4
assert sio.getvalue() == s[:4]
# truncate() accepts long objects
res = sio.truncate(4L)
assert res == 4
assert sio.getvalue() == s[:4]
assert sio.tell() == 6
sio.seek(0, 2)
sio.write(s)
assert sio.getvalue() == s[:4] + s
pos = sio.tell()
res = sio.truncate(None)
assert res == pos
assert sio.tell() == pos
raises(TypeError, sio.truncate, '0')
sio.close()
raises(ValueError, sio.truncate, 0)
def test_tell():
s = u"1234567890"
sio = StringIO(s)
assert sio.tell() == 0
sio.seek(5)
assert sio.tell() == 5
sio.seek(10000)
assert sio.tell() == 10000
sio.close()
raises(ValueError, sio.tell)
def test_roundtrip_translation():
sio1 = StringIO(u'a\nb', newline='\r\n')
pos = sio1.seek(1)
assert sio1.getvalue() == u'a\r\nb'
state = sio1.__getstate__()
sio2 = StringIO()
sio2.__setstate__(state)
assert sio2.getvalue() == u'a\r\nb'
assert sio2.tell() == pos
def test_roundtrip_state():
s = u'12345678'
sio1 = StringIO(s)
sio1.foo = 42
sio1.seek(2)
assert sio1.getvalue() == s
state = sio1.__getstate__()
sio2 = StringIO()
sio2.__setstate__(state)
assert sio2.getvalue() == s
assert sio2.foo == 42
assert sio2.tell() == 2
def test_overseek():
s = u"1234567890"
sio = StringIO(s)
res = sio.seek(11)
assert res == 11
res = sio.read()
assert res == u""
assert sio.tell() == 11
assert sio.getvalue() == s
sio.write(u"")
assert sio.getvalue() == s
sio.write(s)
assert sio.getvalue() == s + u"\0" + s
# File : summary_StringIO.py
# Software: PyCharm
try:
from _io import StringIO
except ImportError:
from io import StringIO
f = StringIO()
f.write('hello world!!!')
print(f.getvalue(), len(f.getvalue()))
f.write('hello world!!!')
print(f.getvalue(), len(f.getvalue()))
f.truncate(0)
f.write('start write!')
print(f.tell())
print("next:\t", f.getvalue(), len(f.getvalue()))
f_test = StringIO('Hello! Hi! Goodbye!')
print("1:\t", f_test.read())
print(f_test.getvalue())
print(f_test.getvalue())
print("2:\t", f_test.read())
print("3:\t", f_test.read())
print("4:\t", f_test.read())
print("next:\t", f_test.getvalue(), len(f_test.getvalue()))
f_test.close()
f.close()
