def test_install_umask(self):
        '''
        Test that files are installed with correct permissions using default
        install umask of 022, regardless of the umask at time the worktree
        was checked out or the build was executed.
        '''
        # Copy source tree to a temporary directory and change permissions
        # there to simulate a checkout with umask 002.
        orig_testdir = os.path.join(self.unit_test_dir, '26 install umask')
        # Create a new testdir under tmpdir.
        tmpdir = os.path.realpath(tempfile.mkdtemp())
        self.addCleanup(windows_proof_rmtree, tmpdir)
        testdir = os.path.join(tmpdir, '26 install umask')
        # Copy the tree using shutil.copyfile, which will use the current umask
        # instead of preserving permissions of the old tree.
        save_umask = os.umask(0o002)
        self.addCleanup(os.umask, save_umask)
        shutil.copytree(orig_testdir, testdir, copy_function=shutil.copyfile)
        # Preserve the executable status of subdir/sayhello though.
        os.chmod(os.path.join(testdir, 'subdir', 'sayhello'), 0o775)
        self.init(testdir)
        # Run the build under a 027 umask now.
        os.umask(0o027)
        self.build()
        # And keep umask 027 for the install step too.
        self.install()

        for executable in [
                'bin/prog',
                'share/subdir/sayhello',
        ]:
            f = os.path.join(self.installdir, 'usr', *executable.split('/'))
            found_mode = stat.filemode(os.stat(f).st_mode)
            want_mode = '-rwxr-xr-x'
            self.assertEqual(want_mode, found_mode,
                             msg=('Expected file %s to have mode %s but found %s instead.' %
                                  (executable, want_mode, found_mode)))

        for directory in [
                'usr',
                'usr/bin',
                'usr/include',
                'usr/share',
                'usr/share/man',
                'usr/share/man/man1',
                'usr/share/subdir',
        ]:
            f = os.path.join(self.installdir, *directory.split('/'))
            found_mode = stat.filemode(os.stat(f).st_mode)
            want_mode = 'drwxr-xr-x'
            self.assertEqual(want_mode, found_mode,
                             msg=('Expected directory %s to have mode %s but found %s instead.' %
                                  (directory, want_mode, found_mode)))

        for datafile in [
                'include/sample.h',
                'share/datafile.cat',
                'share/file.dat',
                'share/man/man1/prog.1',
                'share/subdir/datafile.dog',
        ]:
            f = os.path.join(self.installdir, 'usr', *datafile.split('/'))
            found_mode = stat.filemode(os.stat(f).st_mode)
            want_mode = '-rw-r--r--'
            self.assertEqual(want_mode, found_mode,
                             msg=('Expected file %s to have mode %s but found %s instead.' %
                                  (datafile, want_mode, found_mode)))

        Test that files are installed with correct permissions using default
        install umask of 022, regardless of the umask at time the worktree
        was checked out or the build was executed.
        
unittests/linuxliketests.py