好久都没有专心看书了，心里很难过，现在重温了这本软件测试的书籍，并做了些简单的摘要与大家一起分享。。
Part 1 The Big Picture
Infamous software error case studies
1. Disney’s Lion King,1994-1995
It turns out that Disney failed to test the software on a broad representation of the many different PC models available on the market .The software worked on a few systems – likely the ones that the Disney programmers used to create the game – but not on the most common systems that the general public had.
2. Inter Pentium Floating-point Division bug,1994
Enter the following equation into your PC’s calculator:
(4195835/3145727)* 3145727-4195835
If the answer is zero , your computer is just fine . If you get anything else , you have and old inter Pentium CUP with a floating-point division bug – a software bug burned into a computer chip and reproduced over and over in the manufacturing process.
3. NASA mars polar lander,1999
4. patriot missile defense system,1991
5. the Y2K(year 2000) bug, circa 1974
6. dangerous viewing ahead,2004
What is a bug?
Terms for software failures
Defect variance fault failure problem inconsistency error feature incident bug anomaly
Fault、failure and defect tend to imply a condition that’s really severe , maybe even dangerous.
Anomaly , incident and variance don’t sound quite so negative and are often used to infer unintended operation rather than all-out-failure.
Problem , error , and bug are probably the most generic terms used.
Software bug : a formal definition
For the purposes of this book and much of the software industry , a software bug occurs when one or more of the following five rules is true :
1. the software doesn’t do something that the product specification says it should do
2. the software does something that the product specification says it shouldn’t do
3. the software does something that the product specification doesn’t mention
4. the software doesn’t do something that the product specification doesn’t mention but should
5. the software is difficult to understand , hard to use , slow , or-in the software tester’s eyes-will be viewed by the end user as just plain not right
Why do bugs occur ?
1. bugs are caused for numerous reasons , but , in this sample project analysis , the main cause can be traced to the specification
2. the next largest source of bugs is the design
3. coding errors may be more familiar to you if you’re a programmer
4. the other category is the catch-all for what’s left . some bugs can also be traced to testing errors ; multiple ones that resulted from the same root cause…………
The cost of bugs
the costs are logarithmic – that is ,they increase tenfold as time increases. A bug found and fixed during the early stages when the specification is being written might cost next to nothing , or $1 inour example . the same bug , if not found until the software is coded and tested , might cost $10 to $100 . if a customer finds it , the cost could easily be thousands or even millions of dollars.
What exactly does a software tester do ?
The goal of a software tester is to find bugs , find them as early as possible , and make sure they get fixed.
What makes a good software tester ?
1. they are explorers
2. they are troubleshooters
3. they are relentless
4. they are creative
5. they are perfectionists
6. they exercise good judgment
7. they are tactful and diplomatic
8. they are persuasive
