January 2013
Intermediate to advanced
332 pages
5h 23m
Chinese
Content preview from JAVASCRIPT網頁應用程式設計
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第九章
測試與除錯
每個程式設計師在開發系統時，多少都會進行各種程度不一的測試。即使只是手動執行
一下剛寫好的程式，也算得上是一種測試。不過本章的重點，是說明如何自動化測試
JavaScript 程式—也就是要教你如何撰寫一些可以自動執行的判斷式（assertion）。自動
化測試並不會降低程式裡的臭蟲（bug）數量，但它能大幅提昇程式的品質，並能確保
曾經出現過的臭蟲不會再度出現。目前市面上已經有許多書籍和教學文件，針對各種不
同的測試類型，提供了極為深入且精闢的解說。本章並不打算拾人牙慧，闡述這些重複
的內容（而且我應該也很難解釋的比他們還好）。本章的重點會放在測試 JavaScript 程
式時，一些和其他程式語言不同或需要特別注意的地方。
測試 JavaScript 程式的風氣仍不普及，很多 JavaScript 程式設計師其實都沒有撰寫測試
程式的習慣。我認為這主要應該是因為 JavaScript 的自動化測試實在是太難準備（要考
慮的測試環境範圍太廣）。以 jQuery 函式庫為例，它裡面就準備了數以百計的單元測試
程式，還有用大約十個不同的測試組合（test suites）來模擬它可能會遇到的各種不同執
行環境。所有的單元測試程式，都要分別在所有的測試組合中跑過一輪。先看看 jQuery
支援的瀏覽器有哪些：
• Safari：3.2、4、5、nightly
• Chrome：8、9、10、11
• Internet Explorer：6、7、8、9
• Firefox：2、3、3.5、
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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.