How to use the extractcode.archive.extract_tar function in extractcode

def test_extract_tar_absolute_path(self):
        non_result = '/home/li/Desktop/absolute_folder'
        assert not os.path.exists(non_result)

        test_dir = self.get_temp_dir()
        test_file = self.get_test_loc('archive/tar/tar_absolute.tar')
        archive.extract_tar(test_file, test_dir)

        assert not os.path.exists(non_result)
        result = os.path.join(test_dir, 'home/li/Desktop/absolute_folder/absolute_file')
        assert os.path.exists(result)

def test_extract_targz_from_apache_should_not_return_errors(self):
        # from http://archive.apache.org/dist/commons/logging/source/commons-logging-1.1.2-src.tar.gz
        # failed with ReadError('not a bzip2 file',)
        test_file = self.get_test_loc('archive/tgz/commons-logging-1.1.2-src.tar.gz')
        test_dir = self.get_temp_dir()
        extractor = archive.get_extractor(test_file)
        assert archive.extract_tar == extractor
        result = archive.extract_tar(test_file, test_dir)
        assert [] == result
        assert os.listdir(test_dir)

def test_extract_targz_with_unicode_path_should_extract_without_error(self):
        test_file = self.get_test_loc('archive/tgz/tgz_unicode.tgz')
        test_dir = self.get_temp_dir()
        extractor = archive.get_extractor(test_file)
        assert archive.extract_tar == extractor
        result = archive.extract_tar(test_file, test_dir)
        assert [] == result
        assert os.listdir(test_dir)

def test_extract_tar_with_absolute_path2(self):
        assert not os.path.exists('/tmp/subdir')

        test_file = self.get_test_loc('archive/tar/absolute_path.tar')
        test_dir = self.get_temp_dir()
        archive.extract_tar(test_file, test_dir)

        assert not os.path.exists('/tmp/subdir')
        result = os.path.join(test_dir, 'tmp/subdir/a.txt')
        assert os.path.exists(result)

def test_extract_tar_bz2_basic_bz(self):
        test_file = self.get_test_loc('archive/tbz/tarred_bzipped.bz')
        test_dir = self.get_temp_dir()
        archive.extract_tar(test_file, test_dir)
        result = os.path.join(test_dir, 'e/a/b.txt')
        assert os.path.exists(result)

def test_extract_targz_with_mixed_case_and_symlink(self):
        test_file = self.get_test_loc('archive/tgz/mixed_case_and_symlink.tgz')
        test_dir = self.get_temp_dir()
        result = archive.extract_tar(test_file, test_dir)
        assert [] == result
        import json
        exp_file = self.get_test_loc('archive/tgz/mixed_case_and_symlink.tgz.expected')
        with codecs.open(exp_file, encoding='utf-8') as ef:
            expected_files = json.load(ef)
        check_files(test_dir, map(str, expected_files))

def test_extract_tar_bz2_absolute_path(self):
        assert not os.path.exists('/tmp/subdir')
        test_dir = self.get_temp_dir()
        test_file = self.get_test_loc('archive/tbz/absolute_path.tar.bz2')
        archive.extract_tar(test_file, test_dir)
        assert not os.path.exists('/tmp/subdir')
        result = os.path.join(test_dir, 'tmp/subdir/a.txt')
        assert os.path.exists(result)

def get_gem_metadata(location):
    """
    Return the string content of the metadata of a .gem archive file at
    `location` or None
    """
    extract_loc = None
    try:
        # Extract first level of tar archive
        extract_loc = fileutils.get_temp_dir(prefix='scancode-extract-')
        abs_location = abspath(expanduser(location))
        warnings = archive.extract_tar(abs_location, extract_loc) or []
        if warnings:
            raise Exception('Failed to extract RubyGem .gem file.\n' + '\n'.join(warnings))


        # The gzipped metadata is the second level of archive.
        metadata = os.path.join(extract_loc, 'metadata')
        # or it can be a plain, non-gzipped file
        metadata_gz = metadata + '.gz'

        if os.path.exists(metadata):
            with open(metadata, 'rb') as met:
                content = met.read()

        elif os.path.exists(metadata_gz):
            content, warnings = get_gz_compressed_file_content(metadata_gz)
            if warnings: