view tests/test-atomictempfile.py @ 36037:8de90e006c78

run-tests: report tests that exception occurred in

We now record the test that an exception occurred in. We put this
information to use by aggregating the count of failures in each
test. For each exception, the exception report now prints the total
number of tests having that exception and the test with the least
number of exceptions exhibiting that failure. The exception list
is now sorted by (total count, tests impacted, count of failures
in least failing test).

This allows us to:

* Assess how widespread a failure is. Some exceptions occur a lot
  in a few tests. Others occur over many tests.
* Easily run a test exhibiting an exception without having to find
  a failure in test output.
* Find and fix low hanging fruit (e.g. exceptions that are the
  only failure in a test).

Here's an example of the new output:

199 (4 tests)   /home/gps/src/hg/hgext/blackbox.py:191: %b requires a bytes-like object, or an object that implements __bytes__, not 'str' (test-devel-warnings.t - 1 total)
142 (19 tests)  /home/gps/src/hg/hgext/mq.py:655: list indices must be integers or slices, not bytes (test-hardlinks.t - 1 total)
140 (20 tests)  /home/gps/src/hg/mercurial/patch.py:296: string argument expected, got 'bytes' (test-audit-subrepo.t - 1 total)
101 (15 tests)  /home/gps/src/hg/hgext/convert/convcmd.py:60: encode() argument 1 must be str, not bytes (test-convert-clonebranches.t - 1 total)
90 (2 tests)    /home/gps/src/hg/hgext/mq.py:456: can't concat str to bytes (test-mq-qqueue.t - 1 total)
87 (2 tests)    /home/gps/src/hg/mercurial/branchmap.py:380: %b requires a bytes-like object, or an object that implements __bytes__, not 'FileNotFoundError' (test-branches.t - 2 total)
85 (22 tests)   /home/gps/src/hg/mercurial/sshpeer.py:223: cannot convert 'UUID' object to bytes (test-bundle2-pushback.t - 1 total)
1 (1 tests)     /home/gps/src/hg/mercurial/formatter.py:254: %b requires a bytes-like object, or an object that implements __bytes__, not 'str' (test-debugextensions.t - 2 total)
1 (1 tests)     /home/gps/src/hg/hgext/convert/convcmd.py:420: startswith first arg must be str or a tuple of str, not bytes (test-convert-authormap.t - 2 total)
1 (1 tests)     /home/gps/src/hg/mercurial/revlog.py:797: '>=' not supported between instances of 'NoneType' and 'int' (test-unionrepo.t - 1 total)
1 (1 tests)     /home/gps/src/hg/hgext/show.py:129: %b requires a bytes-like object, or an object that implements __bytes__, not 'str' (test-show.t - 1 total)

Differential Revision: https://phab.mercurial-scm.org/D2138

from __future__ import absolute_import

import glob
import os
import shutil
import tempfile
import unittest

from mercurial import (
    util,
)
atomictempfile = util.atomictempfile

class testatomictempfile(unittest.TestCase):
    def setUp(self):
        self._testdir = tempfile.mkdtemp('atomictempfiletest')
        self._filename = os.path.join(self._testdir, 'testfilename')

    def tearDown(self):
        shutil.rmtree(self._testdir, True)

    def testsimple(self):
        file = atomictempfile(self._filename)
        self.assertFalse(os.path.isfile(self._filename))
        tempfilename = file._tempname
        self.assertTrue(tempfilename in glob.glob(
            os.path.join(self._testdir, '.testfilename-*')))

        file.write(b'argh\n')
        file.close()

        self.assertTrue(os.path.isfile(self._filename))
        self.assertTrue(tempfilename not in glob.glob(
            os.path.join(self._testdir, '.testfilename-*')))

    # discard() removes the temp file without making the write permanent
    def testdiscard(self):
        file = atomictempfile(self._filename)
        (dir, basename) = os.path.split(file._tempname)

        file.write(b'yo\n')
        file.discard()

        self.assertFalse(os.path.isfile(self._filename))
        self.assertTrue(basename not in os.listdir('.'))

    # if a programmer screws up and passes bad args to atomictempfile, they
    # get a plain ordinary TypeError, not infinite recursion
    def testoops(self):
        with self.assertRaises(TypeError):
            atomictempfile()

    # checkambig=True avoids ambiguity of timestamp
    def testcheckambig(self):
        def atomicwrite(checkambig):
            f = atomictempfile(self._filename, checkambig=checkambig)
            f.write('FOO')
            f.close()

        # try some times, because reproduction of ambiguity depends on
        # "filesystem time"
        for i in xrange(5):
            atomicwrite(False)
            oldstat = os.stat(self._filename)
            if oldstat.st_ctime != oldstat.st_mtime:
                # subsequent changing never causes ambiguity
                continue

            repetition = 3

            # repeat atomic write with checkambig=True, to examine
            # whether st_mtime is advanced multiple times as expected
            for j in xrange(repetition):
                atomicwrite(True)
            newstat = os.stat(self._filename)
            if oldstat.st_ctime != newstat.st_ctime:
                # timestamp ambiguity was naturally avoided while repetition
                continue

            # st_mtime should be advanced "repetition" times, because
            # all atomicwrite() occurred at same time (in sec)
            self.assertTrue(newstat.st_mtime ==
                            ((oldstat.st_mtime + repetition) & 0x7fffffff))
            # no more examination is needed, if assumption above is true
            break
        else:
            # This platform seems too slow to examine anti-ambiguity
            # of file timestamp (or test happened to be executed at
            # bad timing). Exit silently in this case, because running
            # on other faster platforms can detect problems
            pass

    def testread(self):
        with open(self._filename, 'wb') as f:
            f.write(b'foobar\n')
        file = atomictempfile(self._filename, mode='rb')
        self.assertTrue(file.read(), b'foobar\n')
        file.discard()

    def testcontextmanagersuccess(self):
        """When the context closes, the file is closed"""
        with atomictempfile('foo') as f:
            self.assertFalse(os.path.isfile('foo'))
            f.write(b'argh\n')
        self.assertTrue(os.path.isfile('foo'))

    def testcontextmanagerfailure(self):
        """On exception, the file is discarded"""
        try:
            with atomictempfile('foo') as f:
                self.assertFalse(os.path.isfile('foo'))
                f.write(b'argh\n')
                raise ValueError
        except ValueError:
            pass
        self.assertFalse(os.path.isfile('foo'))

if __name__ == '__main__':
    import silenttestrunner
    silenttestrunner.main(__name__)