### Question:
ConnectionManager implements Closeable { public Serializer getSerializer() { return serializer; } private  ConnectionManager(ConnectionManager.Builder builder); ClientConfig getClientConfig(); HttpClient getHttpClient(); Serializer getSerializer(); boolean isSessionAutoManaged(); @Override void close();  }### Answer:
@Test @DisplayName("Check serializer") void serializerTest() { assertThat(unit.getSerializer()).isNotNull(); }