from __future__ import print_function
import os

NAME = 'output.txt'

# Open same file for reading and writing.
fw = open(NAME, 'wb')
fr = open(NAME, 'rb')

# Write and then read something from the file.
fw.write(b'first')
fw.flush()
print('first:', fr.read())

# This next line triggers file handle getting stuck on Mac OS X / Python 2
# (works on Linux Python 2 and 3, Mac OS X Python 3 and pypy)
fr.read()

# Write and read some more from the file.
fw.write(b'second')
fw.flush()
print('should be second:', fr.read())

# Reset file read handle to not be at EOF (needed for Mac OS X / Python 2)
fr.seek(0, os.SEEK_CUR)

print('should be empty:', fr.read())

fw.close()
fr.close()