class WriteBufferTest(unittest.TestCase):
    def setUp(self):
        item_writer = GroupingBufferFilesTracker(JsonExportFormatter({}, meta()), 'gz')
        self.write_buffer = WriteBuffer(1000, 1000, item_writer)

    def tearDown(self):
        self.write_buffer.close()

    def test_get_metadata(self):
        # given:
        self.write_buffer.metadata['somekey'] = {'items': 10}
        # then
        self.assertEqual(self.write_buffer.get_metadata('somekey', 'items'), 10,
                         'Wrong metadata')
        self.assertIsNone(self.write_buffer.get_metadata('somekey', 'nokey'))