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Software Testing

Dr. Xin (Judy) Feng Email: xinfeng@uic.edu.hkWeb: http://uic.edu.hk/~XinFeng

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Introductory Stuff Have Fun! Please turn

off your phones!

DODO interact with me!

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Introductory Stuff This will be a relatively interactive

course. Feel free to stop me, shout at me, argue,… etc.

If you have trouble understanding me (I expect that you will),

TELL ME! I will try to speak more clearly and

slowly!

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Outline What is software testing Why do we need the testing How should we do the testing Basic testing strategies

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What is software testing?

Software Testing is an activity to catch bugs in

software applications (include Computer-Aided Language Learning applications)

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Why software testing? Create robust products Reduce the risks (time, money,

life, credit…)

What problems do you think are bugs in a CALL system?

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Some misunderstandings about software testing

Testing is Debugging???

Truth: Testing is to show that programs have bugs Debugging is to find the errors that make

the programs fail

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Some misunderstandings about software testing

Testing is Easy???

Truth: Testing is very expensive. It

consumes almost half of the labour in the software development

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Some misunderstandings about software testing

Testing is Everything???

Truth: Testing is one of the activities to

assure software quality Other activities are necessary

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How to test software? Test cases

used to input to a system to check if the system produces an unexpected result

Two basic testing strategies White-box testing Black-box testing

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White-box testing Test cases are generated based on the

internal structure and code of programs Basic white-box testing strategies

Statement testing Branch testing Path testing

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White-box testingCount spelling errors and grammar errors

Spelling errors > 10

Deduct 10 marks

Grammar errors > 5

Deduct 15 marks

Statement Branch

Path

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Statement testingCount spelling errors and grammar errors

Spelling errors > 10

Deduct 10 marks

Grammar errors > 5

Deduct 15 marks

Statement Every statement must be executed at least once.

Question: At least how many test cases are needed?

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Branch testingCount spelling errors and grammar errors

Spelling errors > 10

Deduct 10 marks

Grammar errors > 5

Deduct 15 marks

Branch

Every Branch must be executed at least once.

Question: At least how many test cases are needed?

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Path testingCount spelling errors and grammar errors

Spelling errors > 10

Deduct 10 marks

Grammar errors > 5

Deduct 15 marks

Path Every path must be executed at least once.

Question: How many paths are there totally?

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Black-box testing Test cases are generated based on the

program requirements Basic black-box testing strategies

Equivalence-class testing Boundary value testing

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Equivalence class testing Categorize the input into the classes

with some similar features Select one or more test cases from each

class

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Equivalence class testing

Students’ marks for grammar and spelling

Grammar marks > 60 and

Spelling marks > 60

Grammar marks > 60 and

Spelling marks ≤ 60

Grammar marks ≤ 60 and

Spelling marks > 60

Grammar marks ≤ 60 and

Spelling marks ≤ 60

Four classes

Pass Supplementary for spelling

Supplementary for grammar

Fail

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Boundary value testing Use the boundary values as well as normal

values to test Software applications tend to fail at the

boundary values

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Boundary value testing

Spelling marks: 0 – 100Grammar marks: 0 - 100

100

100

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Summary Software testing - What, why and how White-box testing

Statement testing Branch testing Path testing

Black-box testing Equivalence class testing Boundary value testing