Chapter1 Software Testing Introduction

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1.6 Software Testing Rules

Test passing rules
Whether all test cases are executed. Whether function design is finished Whether we get enough Bugs
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1.4 Reason of Software Defact
Reasons

of defact:
Deviate from user requirements Requirement report changed often Implement extra functions Function miss


“Aerobus747-400” are made up of 1000,000 parts Qualified rate of every part: 99.9999% Do you know the qualified rate？
（99.9999%）1000000 = 36.79%
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东北大学软件学院
1.3 Basic Concepts of Software Testing
Software

test purpose
Find errors of software Decrease the risk of software doesn’t work
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1.4 Reason of Software Defact

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1.7 Capability for Software Testing
Technique ability Communication ability Suspicion Confidence Patience Analysis ability Cooperation
3
Understand correctly Programming correctly
1.5 Relationship between Software Development and Testing

Defacts can be imported from any phrase during software development，and they will be amplified：
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1.3 Basic Concepts of Software Testing

Concepts related to software testing

Test & debug



Automated test vs. manual operate Don’t know details are OK vs. must know details Correctness proof and how to do with failure vs. correctness proof only Check vs. deduce Plan , under control vs. out of control

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1.3 Basic Concepts of Software Testing

Software defact definition
Doesn’t accord with user expectancy Software function can be executed correctly Defact of Software=Bug All kinds of software problems Inconsistency , user interface fault

Glenford Myers

《The Art of Software Testing》,1979


QA（Quality Assuarance） department , 1976~1985 TCMM（Testing Capability Maturity Model）,1996
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东北大学软件学院
1.1 Why Software Testing is Needed
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1.1 Why Software Testing is Needed
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1.1 Why Software Testing is Needed

Infamous software error case studies
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1.5 Relationship between Software run result coherent? Development and Testing User requirements
user：what I need
5
computer：the result of running Run correctly Input correctly Source code programmer：what should be done computer)
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1.6 Software Testing Rules
Good-enough 80-20
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1.6 Software Testing Rules
Whole test case（valid data、invalid data） Predict the outcome of test case Test independently Problems go beyond specification can’t be ignored regression test Random test should be avoided
Software Testing
Chapter 1 Software Testing Introduction
Contents




1.1 Why Software Testing is Needed 1.2 History of Software Testing 1.3 Basic Concepts of Software Testing 1.4 Reason of Software Defact 1.5 Relationship between Software Development and Testing 1.6 Software Testing Rules 1.7 Capability for Software Testing
Understand correctly Express correctly
requirement specification
1
4
analyst：what I can afford
Understand correctly Design correctly Express correctly
2
design specification designer： how to do 东北大学软件学院 (computer)
（99%）
10000
= 2.25 × 10
-44
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1.2 History of Software Testing

Bill Hetzel give a definition:

“Establish confidence that a program does what it is supposed to do” . 1973

Disney’s Lion King ,1994-1995 Patriot Missile Defense System ,1991
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1.1 Why Software Testing is Needed

Qualified rate of products

Qualified rate of airplane manufacturing industry
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1.6 Software Testing Rules

Infinite test is impossible
Unfound Bug numbers Testing Cost
Best Testing Point
Insufficient Testing
Excess Testing
Testing Degree
1.1 Why Software Testing is Needed

Qualified rate of products

Qualified rate of software

Coding line: 99% Write 10,000 lines code Do you know the qualified rate?

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1.3 Basic Concepts of Software Testing

Defact example：


shortcoming：running slowly Inconsistency ：Ctrl+S can’t save all applications User interface design defact: an button should show 5 words on it ,but only 3 words could be seen
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1.3 Basic Concepts of Software Testing

Software testing definition



Software testing is the essential step which is planned and systematic We can know whether the users expectations are realized Software testing is the key step of software quality assurance
1.3 Basic Concepts of Software Testing

Concepts related to software testing
Error: mistake，people will make mistake during coding Fault: fault is the outcome of error Failure: it will occur when fault is Ｄ efact implemented Incident: no message be displayed when failure occur
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1.3 Basic Concepts of Software Testing

Concepts rቤተ መጻሕፍቲ ባይዱlated to software testing

Correct program



No syntax error No obvious errors during running No improper statements Valid input - correct output Invalid input - correct output Any possible input - correct output