UNIT-1 Software Testing

7/26/2019 UNIT-1 Software Testing

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SOFTWARE ENGINEERING

Top-Down Programming

Divides comple programs in!o "ierarc"# o$mod%les

T"e mod%le a! !op con!rols eec%!ion 'calling(lower level mod%les

)od%lar programming

* Similar !o !op-down programming

One program calls o!"er programs !o wor+!oge!"er as single s#s!em


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S!r%c!%red programming

* Improves comp%!er program ,%ali!#

*Allows o!"er programmers !o easil# read and

modi$# code

* Eac" program mod%le "as one &eginning and

one ending

* T"ree programming cons!r%c!s se,%ence.decision. repe!i!ion/


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T"ree S!r%c!%red Programming 0ons!r%c!s


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Program !es!ing

0an reveal !"e presence o$ errors NOT !"eir

a&sence

A s%ccess$%l !es! is a !es! w"ic" discovers one

or more errors T"e onl# valida!ion !ec"ni,%e $or non-$%nc!ional

re,%iremen!s

S"o%ld &e %sed in con1%nc!ion wi!" s!a!icveri$ica!ion !o provide $%ll 232 coverage


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Tes!ing Principles

All !es!s s"o%ld &e !racea&le !o c%s!omerre,%iremen!s4

Tes!s s"o%ld &e planned long &e$ore !es!ing

&egins Tes!ing s"o%ld &egin 'in !"e small( 3 progress

!oward 'in !"e large(

E"a%s!ive !es!ing is no! possi&le4

To &e mos! e$$ec!ive. !es!ing s"o%ld &econd%c!ed an independen! !"ird par!#


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Tes!ing priori!ies

Onl# e"a%s!ive !es!ing can s"ow a program is

$ree $rom de$ec!s4 5owever. e"a%s!ive !es!ing

is impossi&le

Tes!s s"o%ld eercise a s#s!em6s capa&ili!iesra!"er !"an i!s componen!s

Tes!ing old capa&ili!ies is more impor!an! !"an

!es!ing new capa&ili!ies

Tes!ing !#pical si!%a!ions is more impor!an! !"an

&o%ndar# val%e cases


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Tes!sing approac"es

Arc"i!ec!%ral valida!ion* Top-down in!egra!ion !es!ing is &e!!er a! discovering

errors in !"e s#s!em arc"i!ec!%re

S#s!em demons!ra!ion* Top-down in!egra!ion !es!ing allows a limi!eddemons!ra!ion a! an earl# s!age in !"e developmen!

Tes! implemen!a!ion

* O$!en easier wi!" &o!!om-%p in!egra!ion !es!ing Tes! o&serva!ion

* Pro&lems wi!" &o!" approac"es4 E!ra code ma# &ere,%ired !o o&serve !es!s


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Tes! da!a and !es! cases

Test data Inp%!s w"ic" "ave &een devised

!o !es! !"e s#s!em

Test cases Inp%!s !o !es! !"e s#s!em and!"e predic!ed o%!p%!s $rom !"ese inp%!s i$

!"e s#s!em opera!es according !o i!s

speci$ica!ion


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7evels o$ !es!ing

8ni! !es!ing

In!egra!ion !es!ing

S#s!em !es!ing Accep!ance !es!ing


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Tes! Plane


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T"e !es!ing process

Componenttesting

Systemtesting

Acceptancetesting


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Tes!ing s!ages

0omponen! or %ni! !es!ing

* Individ%al componen!s are !es!ed independen!l#9

* 0omponen!s ma# &e $%nc!ions or o&1ec!s or co"eren!

gro%pings o$ !"ese en!i!ies4 S#s!em !es!ing

* Tes!ing o$ !"e s#s!em as a w"ole4 Tes!ing o$ emergen!

proper!ies is par!ic%larl# impor!an!4

Accep!ance !es!ing

* Tes!ing wi!" c%s!omer da!a !o c"ec+ !"a! !"e s#s!em

mee!s !"e c%s!omer:s needs4


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T#pes o$ !es!ing

De$ec! !es!ing

* Tes!s designed !o discover s#s!em de$ec!s4

*A s%ccess$%l de$ec! !es! is one w"ic" reveals

!"e presence o$ de$ec!s in a s#s!em4

S!a!is!ical !es!ing

* !es!s designed !o re$lec! !"e $re,%ence o$ %ser

inp%!s4 8sed $or relia&ili!# es!ima!ion4


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T"e !es!ing process

0omponen! !es!ing

* Tes!ing o$ individ%al program componen!s

* 8s%all# !"e responsi&ili!# o$ !"e componen! developer

ecep! some!imes $or cri!ical s#s!ems/* Tes!s are derived $rom !"e developer:s eperience

In!egra!ion !es!ing

* Tes!ing o$ gro%ps o$ componen!s in!egra!ed !o crea!e

a s#s!em or s%&-s#s!em

* T"e responsi&ili!# o$ an independen! !es!ing !eam

* Tes!s are &ased on a s#s!em speci$ica!ion


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Tes!ing p"ases

Component

testing

Integration

testing

Software developer Independent testing team


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Tes!ing p"ases

Requirements

specifcation

System

specifcation

System

design

Detailed

design

Module and

unit codeand test

Sub-system

integrationtest plan

System

integrationtest plan

Acceptance

test plan

Service Acceptance

test

System

integration test

Sub-system

integration test


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;lac+-&o !es!ing

An approac" !o !es!ing w"ere !"e program

is considered as a


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;lac+-&o !es!ing

I

e

Input test data

OeOutput test results

System

Inputs causinganomalousbehaviour

Outputs which revealthe presence ofdefects


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E,%ivalence par!i!ioning

Inp%! da!a and o%!p%! res%l!s o$!en $all in!o

di$$eren! classes w"ere all mem&ers o$ a

class are rela!ed

Eac" o$ !"ese classes is an e,%ivalence

par!i!ion w"ere !"e program &e"aves in an

e,%ivalen! wa# $or eac" class mem&er

Tes! cases s"o%ld &e c"osen $rom eac"

par!i!ion


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System

Outputs

Invalid inputs Valid inputs


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Par!i!ion s#s!em inp%!s and o%!p%!s in!o

?.??? and

@@.@@@.e,%ivalence par!i!ions are >?.???. >?.???-@@. @@@

and B

>?. ???

0"oose !es! cases a! !"e &o%ndar# o$ !"esese!s

* ?????. ?@@@@. >????. @@@@@. >???>


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E,%ivalence par!i!ions

Between 10000 and 99999Less than 10000 More than 99999

999910000 50000

10000099999

Input values

Between 4 and 10Less than 4 More than 10

34 7

1110

Number of input values


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Tes!ing g%idelines se,%ences/

Tes! so$!ware wi!" se,%ences w"ic" "ave

onl# a single val%e

8se se,%ences o$ di$$eren! siCes in

di$$eren! !es!s

Derive !es!s so !"a! !"e $irs!. middle and

las! elemen!s o$ !"e se,%ence are

accessed

Tes! wi!" se,%ences o$ Cero leng!"


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Searc" ro%!ine - inp%! par!i!ions

Array Element

Single value In sequence

Single value Not in sequence

More than 1 value First element in sequence

More than 1 value Last element in sequence

More than 1 value Middle element in sequence

More than 1 value Not in sequence

Input sequence (T) Key (Key) Output (Found, L)

17 17 true, 1

17 0 false, ??

17, 29, 21, 23 17 true, 141, 18, 9, 31, 30, 16, 45 45 true, 7

17, 18, 21, 23, 29, 41, 38 23 true, 4

21, 23, 29, 33, 38 25 false, ??


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;inar# searc" - e,%iv4 par!i!ions

Pre-condi!ions sa!is$ied. +e# elemen! in arra#

Pre-condi!ions sa!is$ied. +e# elemen! no! in

arra#

Pre-condi!ions %nsa!is$ied. +e# elemen! in arra#

Pre-condi!ions %nsa!is$ied. +e# elemen! no! in

arra#

Inp%! arra# "as a single val%e Inp%! arra# "as an even n%m&er o$ val%es

Inp%! arra# "as an odd n%m&er o$ val%es


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;inar# searc" e,%iv4 par!i!ions

Mid-point

Elements < Mid Elements > Mid

Equivalence class boundaries


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;o%ndar# val%e anal#sis ;2A/

Ano!"er wa# !o genera!e !es! cases is !o

loo+ $or &o%ndar# val%es4

S%ppose a program !a+es an in!eger as

inp%!4

In !"e a&sence o$ an# in$orma!ion. we

ass%me !"a! ? is a &o%ndar#4 Inp%!s !o

!"e program mig"! lie on !"e &o%ndar# or

on ei!"er side o$ !"e &o%ndar#


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;2A con!in%ed

T"is leads !o !es! inp%!s

?. -H?. and >4

* No!e !"a! !"e val%es -H? and > are on ei!"er side o$

!"e &o%ndar# and are c"osen ar&i!raril#4

No!ice !"a! %sing ;2A we ge!

e,%ivalence classes4 One o$ !"ese !"ree

classes con!ains onl# one val%e ?/. !"e

o!"er !wo are largeJ


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;2A con!in%ed

Now s%ppose !"a! a program !a+es !wo

in!egers and K and !"a! >H and

#>K#H4

In !"is case !"e $o%r sides o$ !"e rec!angle

represen! !"e &o%ndar#4


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;2A con!in%ed

For eample. s%ppose !"a! a program

!a+es a s!ring S and an in!eger as

inp%!s4 T"e ;2A can &e done on an# !#pe

o$ da!a4

cons!rain!s on inp%!s are

* leng!"S/>?? and a&


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;2A con!in%ed

L%s! as we applied ;2A !o inp%! da!a. we

can appl# i! !o o%!p%! da!a4

Doing so gives %s e,%ivalence classes $or!"e o%!p%! domain4

We !"en !r# !o $ind !es! inp%!s !"a! will

cover eac" o%!p%! e,%ivalence class4


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S!r%c!%ral !es!ingMW"i!e ;o Tes!

Some!ime called w"i!e-&o !es!ing

Deriva!ion o$ !es! cases according !o

program s!r%c!%re4 nowledge o$ !"e

program is %sed !o iden!i$# addi!ional !es!

cases

O&1ec!ive is !o eercise all program

s!a!emen!s no! all pa!" com&ina!ions/


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W"i!e-&o !es!ing

Componentcode

Testoutputs

Test data

DerivesTests


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Pa!" !es!ing

T"e o&1ec!ive o$ pa!" !es!ing is !o ens%re !"a! !"e

se! o$ !es! cases is s%c" !"a! eac" pa!" !"ro%g"

!"e program is eec%!ed a! leas! once

T"e s!ar!ing poin! $or pa!" !es!ing is a program$low grap" !"a! s"ows nodes represen!ing

program decisions and arcs represen!ing !"e

$low o$ con!rol

S!a!emen!s wi!" condi!ions are !"ere$ore nodes

in !"e $low grap"


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Program $low grap"s

Descri&es !"e program con!rol $low4 Eac" &ranc"

is s"own as a separa!e pa!" and loops are

s"own arrows looping &ac+ !o !"e loop

condi!ion node

8sed as a &asis $or comp%!ing !"e c#cloma!ic

complei!#


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0on!d44

0omplei!# is comp%!ed in one o$ !"ree wa#s

T"e no4 o$ regions o$ !"e $lowgrap" corrospond

!o !"e c#cloma!ic complei!#4

c#cloma!ic complei!#. 2G/. $or a $low grap" .G . is de$ined as

vG/ EN-H

E is !"e no4 o$ edges. N is !"e no4 o$ nodes 2G/ P>

P is !"e no4 o$ predica!e nodes


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0#cloma!ic complei!#

T"e n%m&er o$ !es!s !o !es! all con!rols!a!emen!s e,%als !"e c#cloma!ic complei!#

0#cloma!ic complei!# e,%als n%m&er o$

condi!ions in a program 8se$%l i$ %sed wi!" care4 Does no! impl#ade,%ac# o$ !es!ing4

Al!"o%g" all pa!"s are eec%!ed. all

com&ina!ions o$ pa!"s are no! eec%!ed


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1

2

3

4

65

7

while bottom top


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Independen! pa!"s

>. H. . . @

>. H. . . Q. . H

>. H. . . =. . H

>. H. . . Q. . H. . @

Tes! cases s"o%ld &e derived so !"a! all o$ !"ese

pa!"s are eec%!ed

A d#namic program anal#ser ma# &e %sed !oc"ec+ !"a! pa!"s "ave &een


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0on!d

0#cloma!ic complei!# $or !"e a&ove diagram

>4 T"e $low grap" "as regions4

H4 2G/ >>-@H

4 2G/>


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e# poin!s

Tes! par!s o$ a s#s!em w"ic" are commonl# %sedra!"er !"an !"ose w"ic" are rarel# eec%!ed

E,%ivalence par!i!ions are se!s o$ !es! casesw"ere !"e program s"o%ld &e"ave in an

e,%ivalen! wa# ;lac+-&o !es!ing is &ased on !"e s#s!em

speci$ica!ion S!r%c!%ral !es!ing iden!i$ies !es! cases w"ic"

ca%se all pa!"s !"ro%g" !"e program !o &eeec%!ed


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)od%le Tes!ingM 8ni! !es!ing

)od%le 0an &e Tes!ed - Facili!a!ed

* S!%& Proced%re !"a! "as !"e Same IMO

Parame!ers )e!"od Signa!%re/ as )issing

;e"avior &%! wi!" Simpli$ied ;e"avior

* Driver 0ode !"a! Sim%la!es !"e 8se o$ )od%le

&eing Tes!ed O!"er )od%les in !"e S#s!em

PROCEDURE

UNDER TEST DRIVERSTUB

CALL CALL

ACCESS TO NONLOCAL VARIABLES


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In!egra!ion !es!ing

Tes!s comple!e s#s!ems or s%&s#s!ems

composed o$ in!egra!ed componen!s

In!egra!ion !es!ing s"o%ld &e &lac+-&o

!es!ing wi!" !es!s derived $rom !"e

speci$ica!ion

)ain di$$ic%l!# is localising errors

Incremen!al in!egra!ion !es!ing red%ces

!"is pro&lem


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Approac"es !o in!egra!ion !es!ing

Top-down !es!ing* S!ar! wi!" "ig"-level s#s!em and in!egra!e

$rom !"e !op-down replacing individ%al

componen!s s!%&s w"ere appropria!e ;o!!om-%p !es!ing

* In!egra!e individ%al componen!s in levels %n!il!"e comple!e s#s!em is crea!ed

In prac!ice. mos! in!egra!ion involves acom&ina!ion o$ !"ese s!ra!egies


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Incremen!al in!egra!ion !es!ing

T3

T2

T1

T4

T5

A

B

C

D

T2

T1

T3

T4

A

B

C

T1

T2

T3

A

B

Test sequence1

Test sequence2

Test sequence3


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Top-down !es!ing

Level 2Level 2Level 2Level 2

Level 1 Level 1Testing

sequence

Level 2stubs

Level 3stubs

. . .


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;o!!om-%p !es!ing

Level NLevel NLevel NLevel NLevel N

Level N1 Level N1Level N1

Testing

sequence

Testdrivers

Testdrivers


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S!ress !es!ing

Eercises !"e s#s!em &e#ond i!s maim%mdesign load4 S!ressing !"e s#s!em o$!en ca%sesde$ec!s !o come !o lig"!

S!ressing !"e s#s!em !es! $ail%re &e"avio%r44S#s!ems s"o%ld no! $ail ca!as!rop"icall#4 S!ress!es!ing c"ec+s $or %naccep!a&le loss o$ serviceor da!a

Par!ic%larl# relevan! !o dis!ri&%!ed s#s!emsw"ic" can e"i&i! severe degrada!ion as ane!wor+ &ecomes overloaded

S ! ! d


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S#s!em. accep!ance. and

regression !es!ing

S#s!em !es! Accep!ance !es! Regression !es!

0"ec+ agains!

re,%iremen!sspeci$ica!ions

0"ec+s s%i!a&ili!# $or %ser Rec"ec+s !es! cases

passed previo%sprod%c!ion versions

Per$ormed developmen! !es! gro%p

Per$ormed !es! gro%pwi!" %ser involvemen!

Per$ormed developmen! gro%p

2eri$ies correc!ness and

comple!ion o$ !"e prod%c!

2alida!es %se$%lness and

sa!is$ac!ion wi!" !"eprod%c!

G%ards agains!

%nin!ended c"anges

S ! ! !i


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S#s!em !es!ing

* 0an &e considered a $inal s!ep in in!egra!ion

!es!ing

*A c"ec+ o$ consis!enc# &e!ween !"e so$!ware

s#s!em and i!s speci$ica!ion Encompasses s#s!em wide proper!ies agains! a

s#s!em speci$ica!ion

* S#s!em. accep!ance. and regression !es!ing

are all concerned wi!" !"e &e"avior o$ a en!ireso$!ware s#s!em


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Alp"a 3 &e!a !es!ing

)os! sMw prod%c! &%ilder %se a process calledalp"a &e!a !es!ing !o %ncover errors !"a! onl#!"e end %ser seems !o $ind4

Alp"a !es!

-is cond%c!ed a! devloper:s si!e ac%s!omer4

-cond%c!ed in !"e con!rolled environmen!4

;e!a !es!

-is cond%c!ed a! oneMmore c%s!omer si!es

!"e end-%ser o$ !"e sMw


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Tes!ing and de&%gging

De$ec! !es!ing and de&%gging are dis!inc!processes

2eri$ica!ion and valida!ion is concerned wi!"

es!a&lis"ing !"e eis!ence o$ de$ec!s in aprogram

De&%gging is concerned wi!" loca!ing andrepairing !"ese errors

De&%gging involves $orm%la!ing a "#po!"esisa&o%! program &e"avio%r !"en !es!ing !"ese"#po!"eses !o $ind !"e s#s!em error


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T"e de&%gging process

Locateerror

Designerror repair

Repairerror

Re-testprogram

Testresults Specification Testcases


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O&1ec!ives

To in!rod%ce so$!ware veri$ica!ion andvalida!ion and !o disc%ss !"e dis!inc!ion&e!ween !"em

To descri&e !"e program inspec!ionprocess and i!s role in 2 3 2

To eplain s!a!ic anal#sis as a veri$ica!ion

!ec"ni,%e To descri&e !"e 0leanroom so$!ware

developmen! process


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Verification vs validation

2eri$ica!ion

Are we &%ilding !"e prod%c! rig"!

T"e so$!ware s"o%ld con$orm !o i!s

speci$ica!ion

2alida!ion

Are we &%ilding !"e rig"! prod%c!

T"e so$!ware s"o%ld do w"a! !"e %ser

reall# re,%ires


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The V & V process

Is a w"ole li$e-c#cle process - 2 3 2 m%s! &e

applied a! eac" s!age in !"e so$!ware process4

5as !wo principal o&1ec!ives

* T"e discover# o$ de$ec!s in a s#s!em* T"e assessmen! o$ w"e!"er or no! !"e s#s!em

is %sa&le in an opera!ional si!%a!ion4


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S!a!ic and d#namic veri$ica!ion

Software inspections 0oncerned wi!" anal#sis o$

!"e s!a!ic s#s!em represen!a!ion !o discover

pro&lems (s!a!ic veri$ica!ion/

*)a# &e s%pplemen! !ool-&ased doc%men! and codeanal#sis

Software testing 0oncerned wi!" eercising and

o&serving prod%c! &e"avio%r d#namic

veri$ica!ion/* T"e s#s!em is eec%!ed wi!" !es! da!a and i!s

opera!ional &e"avio%r is o&served


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S!a!ic and d#namic 232

Formalspecification

High-leveldesign

Requirementsspecification

Detaileddesign

Program

Prototype Dynamic

validation

Staticverification

Documents

UNIT-1 Software Testing