view tests/test-demandimport.py.out @ 35450:e31773898197

run-tests: use context managers for file descriptors

I've seen the following error a few times recently when running the tests with
`yes | ./run-tests.py --local -j9 -i`:

Errored test-add.t: Traceback (most recent call last):
  File "./run-tests.py", line 821, in run
    self.runTest()
  File "./run-tests.py", line 910, in runTest
    if self._result.addOutputMismatch(self, ret, out, self._refout):
  File "./run-tests.py", line 1774, in addOutputMismatch
    rename(test.errpath, test.path)
  File "./run-tests.py", line 571, in rename
    os.remove(src)
WindowsError: [Error 32] The process cannot access the file because it is being
 used by another process: 'c:\\Users\\Matt\\projects\\hg\\tests\\test-add.t.err'

This change doesn't fix the problem, but it seems like a simple enough
improvement.

os = <unloaded module 'os'>
os.system = <built-in function system>
os = <module 'os' from '?'>
util = <unloaded module 'util'>
util.system = <function system at 0x?>
util = <module 'mercurial.util' from '?'>
util.system = <function system at 0x?>
hgweb = <unloaded module 'hgweb'>
hgweb_mod = <unloaded module 'hgweb_mod'>
hgweb = <module 'mercurial.hgweb' from '?'>
fred = <unloaded module 're'>
remod = <unloaded module 're'>
re = <unloaded module 'sys'>
fred = <unloaded module 're'>
fred.sub = <function sub at 0x?>
fred = <proxied module 're'>
remod = <module 're' from '?'>
re = <unloaded module 'sys'>
re.stderr = <open file '<whatever>', mode 'w' at 0x?>
re = <proxied module 'sys'>
pvecproxy = <unloaded module 'pvec'>
pvecproxy.__doc__ = 'A "pvec" is ...'
pvecproxy.__name__ = 'mercurial.pvec'
pvecproxy.__dict__['__name__'] = 'mercurial.pvec'
pvecproxy = <proxied module 'pvec'>
contextlib = <unloaded module 'contextlib'>
contextlib.unknownattr = ImportError: cannot import name unknownattr
__import__('contextlib', ..., ['unknownattr']) = <module 'contextlib' from '?'>
hasattr(contextlibimp, 'unknownattr') = False
node = <module 'mercurial.node' from '?'>