### Question:
AsyncStockRepository { @NonNull public CompletionStage<Stock> save(@NonNull Stock stock) { BoundStatement bound = insert.bind(stock.getSymbol(), stock.getDate(), stock.getValue()); CompletionStage<AsyncResultSet> stage = session.executeAsync(bound); return stage.thenApply(rs -> stock); } AsyncStockRepository(
      CqlSession session,
      @Qualifier("stocks.prepared.insert") PreparedStatement insert,
      @Qualifier("stocks.prepared.deleteById") PreparedStatement deleteById,
      @Qualifier("stocks.prepared.findById") PreparedStatement findById,
      @Qualifier("stocks.prepared.findBySymbol") PreparedStatement findBySymbol,
      Function<Row, Stock> rowMapper); @NonNull CompletionStage<Stock> save(@NonNull Stock stock); @NonNull CompletionStage<Void> deleteById(@NonNull String symbol, @NonNull Instant date); @NonNull CompletionStage<Optional<Stock>> findById(@NonNull String symbol, @NonNull Instant date); @NonNull CompletionStage<Stream<Stock>> findAllBySymbol(
      @NonNull String symbol,
      @NonNull Instant start,
      @NonNull Instant end,
      long offset,
      long limit);  }### Answer:
@Test void should_save_stock_when_save_given_valid_input() { given(insert.bind(stock1.getSymbol(), stock1.getDate(), stock1.getValue())).willReturn(bound); given(session.executeAsync(bound)).willReturn(completedStage(resultSet)); var stockRepository = new AsyncStockRepository(session, insert, delete, findById, findBySymbol, rowMapper); var future = stockRepository.save(stock1); assertThat(future).isNotNull().isCompletedWithValue(stock1); verify(session).executeAsync(bound); }