Software Testing - Second Edition By Ron Patton - Introduction

Introduction

It seems as though each day there’s yet another news story about a computer software problem or security breach: a bank reporting incorrect account balances, a Mars Lander lost in space, a grocery store scanner charging too much for bananas, or a hacker gaining access to millions of credit numbers.

Why does this happen? Can’t computer programmers figure out ways to make software just plain work? Unfortunately, no. As software gets more complex, gains more features, and is more interconnected, it becomes more an more difficult---actually, mathematically impossible---to create a glitch-free program. Despite how competent the programmers are and how much care is taken, there will always be software problems.

This is where software testing comes in. We’ve all found those little Inspector 12 tags in the pockets of our new clothes. Well, software has Inspector 12s, too. Most large software companies are so committed to quality they have one or more testers for each programmer. These jobs span the software spectrum from computer games to factory automation to business applications.

This book, Software Testing, will introduce you to the basics of software testing, necessary to become a successful software tester. You will learn how to immediately find problems in any computer program, how to plan an effective test approach, how to clearly report your findings, and how to tell when your software is ready for release.

引言

似乎每天仍有关于计算机软件问题和安全性漏洞的新闻报道：银行报告出现错误收支平衡、火星登陆者号探测器消失在太空、超市扫描仪器使香蕉收费太高，或者黑客获取数百万张信用卡卡号。

为什么会发生这些事情？难道计算机程序员就不会想办法使软件正常的工作吗？很不幸，没有办法。随着软件变得越来越复杂，功能越来越多，而且内部有更多的互联，那将变得越来越困难，事实上，写出一个无缺陷的程序是绝对不可能的事情。不管程序员的水平有多高，不管程序员多么心细，软件缺陷是一直存在的。

这就是软件测试的由来。我们发现在新衣服的口袋里有12个检验标记。对的，软件也有12个检验标记。大多数大型软件公司都致力于品质，他们为每一个程序员配备一个或更多的测试人员。此类工作涵盖了从计算机游戏到工厂自动化和商业应用领域。

软件测试这本书将给你介绍基本的软件测试基础知识，成为一个优秀软件测试员的必备特质。你将学习如何立即从任何计算机程序中发现问题，如何规划一个有效的测试方法，如何清楚地报告你所发现的问题，以及如何确定软件何时可以发布。

About the Second Edition

When I wrote the first edition of Software Testing, software security issues were just beginning to make the headlines. Hackers and security problems had always been a problem, but with the interconnectivity explosion that was about to occur, few in the industry could predict the impact that security bugs would have on developers and users of computer software.

In this second edition I’ve revisited every chapter to emphasize software security issues and point out how the basic testing techniques covered throughout the book can be used to prevent, find and fix them. I’ve also added a chapter that specifically addresses how to test for software security bugs.

If you’re a reader of the first edition, you know that no matter what you do, your software will still be released with bugs. As you’ll learn in the second edition, this axiom still holds true---even for security problems. However, by applying the lessons taught in this book you’ll go a long way towards assuring that the most important bugs don’t slip through and that your team will create the highest quality and most secure software possible.

关于第二版

当我写《软件测试》第一版的时候，软件安全性问题刚刚引起重视。黑客和安全性问题一直是一个难题，随着即将发生的互联性激增，业内极少有人可以预言安全漏洞会给计算机软件程序员和使用者带来什么影响。

在这本书的第二版中，我重写了每一章中关于软件安全问题的内容，并且指出了本书中有哪些基础测试技术可以用来预防、查找和解决这些问题。我还增加了一个章节专门讨论如何检测软件安全问题。

假如你是本书第一版的读者，你知道不管怎样，软件都将会带着缺陷发布。在第二版中，这个原则将仍然有效，此原则同样适用于软件安全问题。但是，通过应用本书中教授的经验，会帮助你确保不会遗漏重大缺陷，并可能创建高质量高安全性软件。

Who Should Use This Book?

This book is written for three different groups of people:

Ÿ  Students of computer hobbyists interested in software testing as a full-time job,internship, or co-op. Read this book before your interview or before your first day on the job to really impress your new boss.

Ÿ  Career changers wanting to move from their field of experience into the software industry. There are lots of opportunities for non-software experts to apply their knowledge to software testing. For example, a flight instructor could test a flight simulator game, an accountant could test tax preparation software, or a teacher could test a new child education program.

Ÿ  Programmers, software project managers, and other people who make up a software development team who want to improve their knowledge and understanding of what software testing is all about.

本书读着群？

本书针对三类不同人群：

Ÿ  想把软件测试作为全职工作的学生和计算机爱好者，比如实习生，带薪合作实习生。在你面试或者第一天上班前阅读本书，将会使你给老板留下深刻的好印象。

Ÿ  想从自己有经验的行业领域转到软件产业的人，软件测试为那些非软件行业专家提供了很多施展他们学识的机会。比如，飞行教官可以测试飞行类模拟游戏，会计师可以测试税务软件，教师可以测试一个新的儿童教育软件。

Ÿ  所有想要提高和了解什么是软件测试的程序员、软件项目经理，以及软件开发团对的其他人员。

What This Book Will Do for you

In this book you will learn something about nearly every aspect of software testing:

Ÿ  How software testing fits into the software development process

Ÿ  Basic and advanced software testing technique

Ÿ  Applying testing skills to common testing tasks

Ÿ  Improving test efficiency with automation

Ÿ  Planning and document your test effort

Ÿ  Effectively reporting the problems you find

Ÿ  Measuring your test effort and your product’s progress

Ÿ  Knowing the difference between testing and quality assurance

Ÿ  Finding a job as a software tester

本书可以为你带来什么

你几乎可以从本书中学到软件测试的方方面面：

Ÿ  软件测试如何融入软件开发过程

Ÿ  基础和高阶的软件测试技术

Ÿ  在日常工作任务中应用测试技术

Ÿ  运用自动化提高测试效率

Ÿ  规划和文档化测试工作

Ÿ  有效报告你发现的问题

Ÿ  评估你的测试工作和产品进展

Ÿ  了解测试与质量保证之间的区别

Ÿ  找一个软件测试员的工作

Software Necessary to Use This Book

The methods presented in this book are generic and can be applied to testing any type of computer software. But, to make the examples familiar and usable by most people, they are based on simple programs such as Calculator, Notepad, and WordPad included with Windows XP and Windows NT/2000.

Even if you’re using a Mac or a PC running Linux or another operating system, you will likely have similar programs available on your computer that you can easily adapt to the text. Be creative! Creativity is one trait of a good software tester.

阅读本书时必需的软件

本书中介绍的方法都是通用的，可以用来测试任何类型的计算机软件。但是，为了使示例能让大多数人熟悉和易用，需要一些基于Windows Xp和Windows NT/2000的简单程序，比如计算器、记事本和写字板。

即使是使用苹果机或者运行LINUX或者其他操作系统的个人电脑，也将会有类似的电脑程序可以方便的打开文本文件，有创意！创新是一个优秀软件测试员的特质。

NOTE

The examples used throughout this book of various applications, software bugs, and software tools are in on way intended as an endorsement or a disparagement of the software. They’re simply used to demonstrate the concepts of software testing.

注意

本书中用到的所有示例，包括各种应用软件、软件缺陷和软件测试工具，并不代表认同或排斥该软件。它们只是用来说明软件测试的概念。

Study Notes:

Mathematically impossible数学上是不可能的，就是指绝对不可能发生的