July 2019
Intermediate to advanced
480 pages
9h 35m
Chinese
Content preview from 持續交付｜使用Java
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290
| 第十一章
Smith 的整篇文章都值得一讀。你必須記得一個核心概念：雖然單元測試與驗收測試
的覆蓋率可能比較低（例如，與端對端測試相較之下），但單元測試可以驗證作品的意
圖，而驗收測試可以按需求來檢查作品。這代表程式碼的行為，與它和系統其他部分的
互動都是可以驗證的，而且可以在短暫的時間內透過最低限度的協調來完成。例如，只
試著使用端對端測試來驗證部分 app 的一系列邊緣案例可能沒有什麼效果，因為你必須
對相關的資料儲存體進行許多協調，而且每一回合的測試都要花長的時間啟動系統、執
行測試，再卸除所有東西。
建構正確的回饋迴圈
測試可以讓你建立一個回饋迴圈，通知開發者產品是否正常運作。理想的回饋迴圈有這
些屬性：
快速
沒有開發者可以忍受需要等待好幾個小時或好幾天之後，才能知道修改是否成功。
有時不成功的修改（沒有人是完美的）需要讓你運行回饋迴圈多次，快速的回饋迴
圈可實現更快速的修改，如果迴圈夠快，開發者甚至可以先執行測試再 check in 修
改。
可靠
沒有開發者願意花好幾個小時對測試程式進行除錯，然後才發現它只是個不穩定的
測試（flaky test）
1
。不穩定的測試會降低開發者對測試的信任程度，不穩定的測試
通常會被忽略，即使它們真的找到問題了。不穩定的測試也會加入沒必要的延遲：
當開發者懷疑測試失敗可能是假的時，他們的第一反應是再執行它一次，而不是進
行調查。
隔離故障
為了修復 bug，開發者必須找出造成 bug 的那幾行程式。當產品有上百萬行程式
時，bug 可能在任何地方出現，debug
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.