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Python

''' Contexts for *with* statement providing temporary directories
'''
import os
from contextlib import contextmanager
from shutil import rmtree
from tempfile import mkdtemp
@contextmanager
def tempdir():
"""Create and return a temporary directory. This has the same
behavior as mkdtemp but can be used as a context manager.
Upon exiting the context, the directory and everything contained
in it are removed.
Examples
--------
>>> import os
>>> with tempdir() as tmpdir:
... fname = os.path.join(tmpdir, 'example_file.txt')
... with open(fname, 'wt') as fobj:
... _ = fobj.write('a string\\n')
>>> os.path.exists(tmpdir)
False
"""
d = mkdtemp()
yield d
rmtree(d)
@contextmanager
def in_tempdir():
''' Create, return, and change directory to a temporary directory
Examples
--------
>>> import os
>>> my_cwd = os.getcwd()
>>> with in_tempdir() as tmpdir:
... _ = open('test.txt', 'wt').write('some text')
... assert os.path.isfile('test.txt')
... assert os.path.isfile(os.path.join(tmpdir, 'test.txt'))
>>> os.path.exists(tmpdir)
False
>>> os.getcwd() == my_cwd
True
'''
pwd = os.getcwd()
d = mkdtemp()
os.chdir(d)
yield d
os.chdir(pwd)
rmtree(d)
@contextmanager
def in_dir(dir=None):
""" Change directory to given directory for duration of ``with`` block
Useful when you want to use `in_tempdir` for the final test, but
you are still debugging. For example, you may want to do this in the end:
>>> with in_tempdir() as tmpdir:
... # do something complicated which might break
... pass
But, indeed, the complicated thing does break, and meanwhile, the
``in_tempdir`` context manager wiped out the directory with the
temporary files that you wanted for debugging. So, while debugging, you
replace with something like:
>>> with in_dir() as tmpdir: # Use working directory by default
... # do something complicated which might break
... pass
You can then look at the temporary file outputs to debug what is happening,
fix, and finally replace ``in_dir`` with ``in_tempdir`` again.
"""
cwd = os.getcwd()
if dir is None:
yield cwd
return
os.chdir(dir)
yield dir
os.chdir(cwd)