How to use the ffpuppet.checks.CheckLogContents function in ffpuppet

def test_02(self):
        "test CheckLogContents()"
        # input contains token
        with open(self.tmpfn, "w") as in_fp:
            in_fp.write("blah\nfoo\ntest\n123")
        checker = CheckLogContents([self.tmpfn], [re.compile("test")])
        self.assertTrue(checker.check())
        with open(self.tmpfn, "wb") as log_fp:
            checker.dump_log(log_fp)
            self.assertGreater(log_fp.tell(), 1)
        # input does not contains token
        checker = CheckLogContents([self.tmpfn], [re.compile("no_token")])
        self.assertFalse(checker.check())
        # check a 2nd time
        self.assertFalse(checker.check())
        with open(self.tmpfn, "wb") as log_fp:
            checker.dump_log(log_fp)
            self.assertEqual(log_fp.tell(), 0)
        # log does not exist
        checker = CheckLogContents(["missing_log"], [re.compile("no_token")])
        self.assertFalse(checker.check())
        with open(self.tmpfn, "wb") as log_fp:

checker = CheckLogContents([self.tmpfn], [re.compile("no_token")])
        self.assertFalse(checker.check())
        # check a 2nd time
        self.assertFalse(checker.check())
        with open(self.tmpfn, "wb") as log_fp:
            checker.dump_log(log_fp)
            self.assertEqual(log_fp.tell(), 0)
        # log does not exist
        checker = CheckLogContents(["missing_log"], [re.compile("no_token")])
        self.assertFalse(checker.check())
        with open(self.tmpfn, "wb") as log_fp:
            checker.dump_log(log_fp)
            self.assertEqual(log_fp.tell(), 0)
        # input exceeds chunk_size
        try:
            CheckLogContents.chunk_size = CheckLogContents.buf_limit
            with open(self.tmpfn, "w") as in_fp:
                in_fp.write("A" * (CheckLogContents.buf_limit - 2))
                in_fp.write("test123")
                in_fp.write("A" * 20)
            checker = CheckLogContents([self.tmpfn], [re.compile("test123")])
            self.assertFalse(checker.check())
            self.assertTrue(checker.check())
        finally:
            CheckLogContents.chunk_size = 0x20000
        with open(self.tmpfn, "wb") as log_fp:
            checker.dump_log(log_fp)
            self.assertGreater(log_fp.tell(), 1)

checker.dump_log(log_fp)
            self.assertEqual(log_fp.tell(), 0)
        # log does not exist
        checker = CheckLogContents(["missing_log"], [re.compile("no_token")])
        self.assertFalse(checker.check())
        with open(self.tmpfn, "wb") as log_fp:
            checker.dump_log(log_fp)
            self.assertEqual(log_fp.tell(), 0)
        # input exceeds chunk_size
        try:
            CheckLogContents.chunk_size = CheckLogContents.buf_limit
            with open(self.tmpfn, "w") as in_fp:
                in_fp.write("A" * (CheckLogContents.buf_limit - 2))
                in_fp.write("test123")
                in_fp.write("A" * 20)
            checker = CheckLogContents([self.tmpfn], [re.compile("test123")])
            self.assertFalse(checker.check())
            self.assertTrue(checker.check())
        finally:
            CheckLogContents.chunk_size = 0x20000
        with open(self.tmpfn, "wb") as log_fp:
            checker.dump_log(log_fp)
            self.assertGreater(log_fp.tell(), 1)

log.debug("launched firefox with pid: %d", self._proc.pid)
            bootstrapper.wait(self.is_healthy, timeout=launch_timeout, url=location)
        finally:
            bootstrapper.close()
            if prefs_js is not None and os.path.isfile(os.path.join(self.profile, "Invalidprefs.js")):
                raise InvalidPrefs("%r is invalid" % prefs_js)

        if log_limit:
            self._checks.append(CheckLogSize(
                log_limit,
                self._logs.get_fp("stderr").name,
                self._logs.get_fp("stdout").name))
        if memory_limit:
            self._checks.append(CheckMemoryUsage(self.get_pid(), memory_limit))
        if self._abort_tokens:
            self._checks.append(CheckLogContents(
                [self._logs.get_fp("stderr").name, self._logs.get_fp("stdout").name],
                self._abort_tokens))

        self._launches += 1

def __init__(self, log_files, search_tokens):
        assert log_files, "log_files is empty"
        assert search_tokens, "search_tokens is empty"
        super(CheckLogContents, self).__init__()
        self.logs = list()
        for log_file in log_files:
            self.logs.append({"fname": log_file, "buffer": "", "offset": 0})
        self.tokens = search_tokens