tests/test-simplekeyvaluefile.py

repair: use context manager for lock management

If repo.lock() raised inside of the try block, 'tr' would have been None in the
finally block where it tries to release().  Modernize the syntax instead of just
winching the lock out of the try block.

I found several other instances of acquiring the lock inside of the 'try', but
those finally blocks handle None references.  I also started switching some
trivial try/finally blocks to context managers, but didn't get them all because
indenting over 3x for lock, wlock and transaction would have spilled over 80
characters.  That got me wondering if there should be a repo.rwlock(), to handle
locking and unlocking in the proper order.

It also looks like py27 supports supports multiple context managers for a single
'with' statement.  Should I hold off on the rest until py26 is dropped?

from __future__ import absolute_import

import unittest
import silenttestrunner

from mercurial import (
    error,
    scmutil,
)

class mockfile(object):
    def __init__(self, name, fs):
        self.name = name
        self.fs = fs

    def __enter__(self):
        return self

    def __exit__(self, *args, **kwargs):
        pass

    def write(self, text):
        self.fs.contents[self.name] = text

    def read(self):
        return self.fs.contents[self.name]

class mockvfs(object):
    def __init__(self):
        self.contents = {}

    def read(self, path):
        return mockfile(path, self).read()

    def readlines(self, path):
        return mockfile(path, self).read().split('\n')

    def __call__(self, path, mode, atomictemp):
        return mockfile(path, self)

class testsimplekeyvaluefile(unittest.TestCase):
    def setUp(self):
        self.vfs = mockvfs()

    def testbasicwriting(self):
        d = {'key1': 'value1', 'Key2': 'value2'}
        scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write(d)
        self.assertEqual(sorted(self.vfs.read('kvfile').split('\n')),
                         ['', 'Key2=value2', 'key1=value1'])

    def testinvalidkeys(self):
        d = {'0key1': 'value1', 'Key2': 'value2'}
        self.assertRaises(error.ProgrammingError,
                          scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write,
                          d)
        d = {'key1@': 'value1', 'Key2': 'value2'}
        self.assertRaises(error.ProgrammingError,
                          scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write,
                          d)

    def testinvalidvalues(self):
        d = {'key1': 'value1', 'Key2': 'value2\n'}
        self.assertRaises(error.ProgrammingError,
                          scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write,
                          d)

    def testcorruptedfile(self):
        self.vfs.contents['badfile'] = 'ababagalamaga\n'
        self.assertRaises(error.CorruptedState,
                          scmutil.simplekeyvaluefile(self.vfs, 'badfile').read)

if __name__ == "__main__":
    silenttestrunner.main(__name__)