ISTQBCH4

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Dynamic Testing Techniques

1 Principles 2 Lifecycle

4 Dynamic test

techniques

3 Static testing

5 Management 6 Tools

Software Testing

ISTQB / ISEB Foundation Exam Practice

hapter 4

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ontents

!hat is a testing technique"

#lac$ an% !hite &o' testing

#lac$ &o' test techniques

!hite &o' test techniques(rror )uessing


1 2 3

4 5 6


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Why dynamic test techniques?

('hausti*e testing +use of all possi&le inputs

an% con%itions, is impractical

- must use a subset of all possible test casesmust use a subset of all possible test cases

- must have high probability of detecting faultsmust have high probability of detecting faults -ee% thought processes that help us select

test cases more intelligently

-test case design techniques are such thoughttest case design techniques are such thoughtprocessesprocesses

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What is a testing technique?

a proce%ure for selecting or %esigning tests

&ase% on a structural or functional mo%el of

the soft.are

successful at fin%ing faults /&est/ practice

a .ay of %eri*ing goo% test cases

a .ay of o&0ecti*ely measuring a test effort

Testing should be rigorous, thorough and systematic

Testing should be rigorous, thorough and systematic

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Using techniques makes testing much more effectiveUsing techniques makes testing much more effective

Advantages of techniques

Different people similar pro&a&ility fin% faults

- gain some independence of thoughtgain some independence of thought

(ffecti*e testing fin% more faults

- focus attention on specific types of faultfocus attention on specific types of fault

- know you're testing the right thingknow you're testing the right thing

(fficient testing fin% faults .ith less effort

- avoid duplicationavoid duplication- systematic techniques are measurablesystematic techniques are measurable

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Measurement

&0ecti*e assessment of thoroughness of

testing +.ith respect to use of each technique,

- useful for comparison of one test effort to anotheruseful for comparison of one test effort to another

(g

Project A

60% Equivalence

partitions

50% Boundaries

75% Branches

Project B

40% Equivalence

partitions

45% Boundaries

60% Branches

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ontents






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4 5 6


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Three types of systematic technique

Static +none'ecution,

examination of documentation,examination of documentation,source code listings, etc.source code listings, etc.

unctional +#lac$ #o',

based on behaviour /based on behaviour /functionality of softwarefunctionality of software

Structural +!hite #o',

based on structurebased on structureof softwareof software

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Black box versus hite box?

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ontents






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Black Box test design and

measurement techniques Techniques %efine% in #S =>252- quivalence partitioningquivalence partitioning

- !oundary value analysis!oundary value analysis

- "tate transition testing"tate transition testing

- #ause-effect graphing#ause-effect graphing

- "yntax testing"yntax testing

- $andom testing$andom testing 9lso %efines ho. to specify other techniques

? @es

? -o

9lso a measurement

technique"

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!quivalence partitioning "!#$

- divide %partition& the inputs, outputs, etc. into areasdivide %partition& the inputs, outputs, etc. into areaswhich are the same %equivalent&which are the same %equivalent&

- assumption if one value works, all will workassumption if one value works, all will work

- one from each partition better than all from oneone from each partition better than all from one

1 1AA 1A1A

valid invalidinvalid

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Boundary value analysis "B%A$

- faults tend to lurk near boundariesfaults tend to lurk near boundaries

- good place to look for faultsgood place to look for faults

- test values on both sides of boundariestest values on both sides of boundaries

1 1AA 1A1A

valid invalidinvalid

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!xample& 'oan

application

ustomer -ame

9ccount num&er

Loan amount requeste%

Term of loan

Monthly repayment

&er'

(epa$ent'

)nterest rate'

&otal paid back'

6 di!its* +st

non,-ero

.500 to ./000

+ to 0 $ears

1iniu .+0

2,64 chars3

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(ustomer name

-um&er of characters

2 64 65in*ali% *ali% in*ali%

1

Conditions ValidPartitions

InvalidPartitions

ValidBoundaries

InvalidBoundaries

Customername

2 to 64 charsvalid chars

< 2 chars> 64 charsinvalid chars

2 chars64 chars

1 chars65 chars0 chars

;ali% characters 9ny

other

9BaCspace

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Account number

5 6 =in*ali%

*ali%in*ali%

num&er of %igits

first characterin*ali% Cero

*ali% nonCero

Conditions Valid

Partitions

Invalid

Partitions

Valid

Boundaries

Invalid

BoundariesAccount

number

6 diits

1stnon!"ero

< 6 diits

> 6 diits1stdiit # 0non!diit

100000

$$$$$$

5 diits

% diits0 diits

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'oan amount

5AA >AAA >AA1

in*ali% *ali% in*ali%

4>>

Conditions Valid

Partitions

Invalid

Partitions

Valid

Boundaries

Invalid

Boundaries

&oan

amount

500 ! $000 < 500

>$000

0non!numericnull

500

$000

4$$

$001

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(ondition template

on%itions ;ali%Partitions Tag >>>>

#3

#4

5 %igits

= %igitsA %igits

D4

D5D6

Loanamount

5AA >AAA ;5 E 5AAF>AAAA

nonintegernull

GH

G>

G1A

G11G12

5AA>AAA

#5

#6

4>>>AA1

D=

DH

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)esign test cases

Test

ase

Description ('pecte% utcome -e. Tags

o*ere%

1

2

-ame :ohn Smith

9cc no 123456

Loan 25AA

Term 3 years

-ame 9#

9cc no 1AAAAA

Loan 5AA

Term 1 year

Term 3 years

epayment =>H6

6

Term 1 year

epayment 44HA

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Why do both !# and B%A?

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Test ob*ectives?

or a thorough approach ;PJ

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)ecision tables

e'plore com&inations of inputsJ situations or

e*entsJ

it is *ery easy to o*erloo$ specific

com&inations of input start &y e'pressing the input con%itions of

interest so that they are either T7( or 9LS(

record found

file exists

code valid

policy expired

account in credit

due date 0 current date

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!xample& student access

9 uni*ersity computer system allo.s stu%ents

an allocation of %isc space %epen%ing on their

pro0ects

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'ist the input and output conditions

list the 1output

conditions2 under the

input conditions

+nput (onditions

+alid username

+alid password

3ccount in credit,utput (onditions

4ogin accepted

$estricted access

list the 1input

conditions2 in the first

column of the table

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)etermine input combinations

a%% columns to the ta&le for each unique

com&ination of input con%itions

each entry in the ta&le may &e either KT for

trueJ K for false+nput (onditions

+alid username 5 5 5 5 6 6 6 6

+alid password 5 5 6 6 5 5 6 63ccount in credit 5 6 5 6 5 6 5 6

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-ationalise input combinations

some com&inations may &e impossi&le or not

of interest

some com&inations may &e Kequi*alent

use a hyphen to %enote %ont care

+nput (onditions

+alid username 6 5 5 5

+alid password - 6 5 5

3ccount in credit - - 6 5

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(omplete the table

%etermine the e'pecte% output con%itions foreach com&ination of input con%itions

+nput (onditions




,utput (onditions

4ogin accepted 6 6 5 5

$estricted access - - 5 6

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)etermine test case groups each column is at least one test case

+nput (onditions




,utput (onditions

4ogin accepted 6 6 5 5

$estricted access - - 5 6

Tags A B ( )

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)esign test cases

usually one test case for each column &ut can&e none or se*eral

Test )escription !xpected ,utcome Tag

+ sernae Brb )nvalid usernae A

2 sernaeusernaetoolon!

)nvalid usernae A

sernae BobPassord abcd

)nvalid passord B

4 alid user* no disc

space

(estricted access

5 alid user ith discspace

nrestricted access

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-ationalising outputs

7 5 6 6

8 6 5 6

9 6 6 5 (utput 7 8 9

if outputs or effects are mutually e'clusi*eJ

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-ationalising dangers

rationalising is &ase% on assumptions

assumptions may &e .rongN

assumptions shoul% &e state%

assumptions may change o*er time &e a.are of the %angers

- filling in the full table may find errors which will befilling in the full table may find errors which will be

missed if you rationalisemissed if you rationalise

- it is possible to rationalise too farit is possible to rationalise too far

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!xtending decision tables

(ntries can &e more than 0ust Ktrue or Kfalse

- completing table needs to be done carefullycompleting table needs to be done carefully

- rationalising becomes more importantrationalising becomes more important

(g

#ode : ;, now 5 5 6 6 5 5 6 6 5 5 6 6#lass 3 product 5 6 5 6 5 6 5 6 5 6 5 6

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)ecision Tables in relation to !# and

B%A)nput value 8utput value

9A:;E

&(E

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ontents




!hite &o' test techniques

(rror )uessing


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White Box test design and

measurement techniques Techniques %efine% in #S =>252

- "tatement testing"tatement testing

- !ranch / ?ecision testing!ranch / ?ecision testing

- ?ata flow testing?ata flow testing- !ranch condition testing!ranch condition testing

- !ranch condition combination testing!ranch condition combination testing

- @odified condition decision testing@odified condition decision testing

- 4#"3A testing4#"3A testing 9lso %efines ho. to specify other techniques

? @es

? -o

9lso a measurementtechnique"

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Stronger structural

techniques (differentstructural elements)

More tests

.sing structural coverage

Increasing coverage

o*erage O"

!hat/s

co*ere%"

esults O"

(nough

tests"Spe

c

Spe

c Soft.areSoft.areTests

More testsMore testsMore testsMore testsMore testsMore testsMore tests

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The test coverage trap

Structure exercised,insufficient function

Structure exercised,insufficient function

Function exercised,

insufficient structure

Function exercised,

insufficient structure

better testingbetter testing

% ;tateent % ecision % ondition obination

Structural teste%ness

unctionalteste%ness

!!" coverage does

not mean !!" tested#

!!" coverage does

not mean !!" tested#$overage is not

Thoroughness

$overage is not

Thoroughness

;tateent covera!e

;tateent covera!e

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Statement coverage

percentage of e'ecuta&le statements

e'ercise% &y a test suite

number of statements exercisednumber of statements exercised

total number of statementstotal number of statements e'ample

- program has ;BB statementsprogram has ;BB statements

- tests exercise CD statementstests exercise CD statements

- statement coverage : CDEstatement coverage : CDE

?

Typical a% hoc testing achie*es 6A =5ITypical a% hoc testing achie*es 6A =5I

;tateent covera!e

is norall$ easured

b$ a so"tare tool3

!

is norall$ easured

b$ a so"tare tool3

b$

this test case* e have achieved

+00% stateent covera!e

rea%+a,

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)ecision coverage

"Branch coverage$ percentage of %ecision outcomes

e'ercise% &y a test suite

number of decisions outcomes exercisednumber of decisions outcomes exercised

total number of decision outcomestotal number of decision outcomes e'ample

- program has ;

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#aths through code

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