8/9/2019 ISTQBCH3

1/47

Static

Testing

1 Principles 2 Lifecycle

4 Dynamic testtechniques

3 Static testing

5 Management 6 Tools

Software TestingISTQB / ISEB Foundation Exam Practice

hapter 3

8/9/2019 ISTQBCH3

2/47

Contents

Reviews and the test process

Types of review

Static analysis

8/9/2019 ISTQBCH3

3/47

People techniques

individual:desk-checking, data-stepping, proof-reading

group:Reviews (infor al ! for al": for consensus#alkthrough: for education$nspection ( ost for al": to find faults

Static techniques !o not e"ecute co!e

Static techniques !o not e"ecute co!e

8/9/2019 ISTQBCH3

4/47

%enefits of reviews

&evelop ent productivity i prove entReduced develop ent ti escales

Reduced testing ti e and cost'ifeti e cost reductionsReduced fault levels

$ proved custo er relationsetc

8/9/2019 ISTQBCH3

5/47

Reviews are cost-effective

)* ti es reduction in faults reaching test, testingcost reduced +y * to .*

/and+ook of #alkthroughs, $nspections ! TechnicalReviews - 0reed an ! #ein+erg

reduce faults +y a factor of )*

Structured #alkthroughs - 1ourdon

8/9/2019 ISTQBCH3

6/47

2 reduction in schedules, re ove .* -3 of faults at each stage, 2. ti es

reduction in aintenance cost, any others

Software $nspection - 4il+ ! 4raha

8/9/2019 ISTQBCH3

7/47

#hat can +e $nspected5 Anything written downcan be Inspected policy, strategy, +usiness plans, arketing or

advertising aterial, contractssyste require ents, feasi+ility studies,acceptance test plans

test plans, test designs, test cases, testresults

8/9/2019 ISTQBCH3

8/47

syste designs, logical ! physicalsoftware code

user anuals, procedures, training aterial

8/9/2019 ISTQBCH3

9/47

#hat can +e reviewed5

anything which could +e $nspectedi e anything written down

plans, visions, 6+ig picture7, strategicdirections, ideaspro8ect progress

work co pleted to schedule, etc

6Should we develop this7 arketing options

8/9/2019 ISTQBCH3

10/47

#hat to review 9 $nspect5

Tests

Tests

Tests

Tests

#equirements

Design

o!e

$unctions

%ntegration T

&nit Test

'ccept( Test

System Test

8/9/2019 ISTQBCH3

11/47

Costs of reviews

Rough guide: -) of develop ent efforthalf day a week is )*

ffort required for reviewsplanning (+y leader 9 oderator"preparation 9 self-study checking

eetingfi;ing 9 editing 9 follow-up

recording ! analysis of statistics 9 etricsprocess i prove ent (should

8/9/2019 ISTQBCH3

12/47

Contents

Reviews and the test process

Types of reviewStatic analysis

Static testing

1 2

4 5

3

6

ISTQB / ISEB Foundation Exam Practice

8/9/2019 ISTQBCH3

13/47

Types of review of docu ents

$nfor al Reviewundocu ented

widely viewed as useful and cheap (+ut no one canprove itor ally docu ented,

fault-finding Can +e rather su+8ective

8/9/2019 ISTQBCH3

14/47

&ecision- aking Review:group discusses docu ent and akes a decision a+outthe content, e g how so ething should +e done, go or

no-go decision, or technical co ents

8/9/2019 ISTQBCH3

15/47

Types of review of docu ents

#alkthroughauthor guides the group through a docu ent and his orher thought processes, so all understand the sa ething, consensus on changes to ake

$nspection:for al individual and group checking, using sourcesand standards, according to generic and specific rulesand checklists, using entry and e;it criteria, 'eader

ust +e trained ! certified, etrics required

8/9/2019 ISTQBCH3

16/47

Reviews in general )

?+8ectives 9 goalsvalidation ! verification against specifications !standardsachieve consensus (e;cluding $nspection"process i prove ent (ideal, included in$nspection"

8/9/2019 ISTQBCH3

17/47

Reviews in general 2

=ctivitiesplanningoverview 9 kick-off eeting ($nspection"preparation 9 individual checkingreview eeting (not always"follow-up (for so e types"

etrics recording ! analysis ($nspections andso eti es reviews"

8/9/2019 ISTQBCH3

18/47

Reviews in general @

Roles and responsi+ilities'eader 9 oderator - plans the review 9 $nspection,chooses participants, helps ! encourages,conducts the eeting, perfor s follow-up,

anages etrics =uthor of the docu ent +eing reviewed 9$nspected

8/9/2019 ISTQBCH3

19/47

Reviewers 9 $nspectors - specialised fault-findingroles for $nspectionAanagers - e;cluded fro so e types of review,need to plan pro8ect ti e for review 9 $nspection?thers: e g $nspection9 review Co-ordinator

8/9/2019 ISTQBCH3

20/47

Reviews in general B

&elivera+lesChanges (edits" in review productChange requests for source docu ents (predecessordocu ents to product +eing reviewed 9 $nspected"Process i prove ent suggestions

to the review 9 $nspection processto the develop ent process which produced the product 8ust

reviewed 9 $nspectedAetrics ($nspection and so e types of review"

8/9/2019 ISTQBCH3

21/47

Reviews in general

Pitfalls (they don t always work

8/9/2019 ISTQBCH3

22/47

'ack of anage ent support - 6lip service7 - wantthe done, +ut don t allow ti e for the tohappen in pro8ect schedules

0ailure to i prove processes (gets disheartening 8ust getting +etter at finding the sa e thing overagain"

8/9/2019 ISTQBCH3

23/47

$nspection is different

D the docu ent to +ereviewed is given out inadvance

D typically doEens ofpages to review

D instructions are Fpleasereview thisF

D not ust product!sources

Dchun" or samp#e

D training! ro#es

8/9/2019 ISTQBCH3

24/47

$nspection is different

D so e people have ti eto look through it and

ake co ents +efore

the eeting (which isdifficult to arrange"

D the eeting often lastsfor hours

entry criteria tomeeting! may not beworth ho#ding

$ max%! often muchshorter

8/9/2019 ISTQBCH3

25/47

$nspection is different

D F$ donGt like thisF

D uch discussion, so ea+out technicalapproaches, so e a+outtrivia

D donGt really know if it wasworthwhile, +ut we keepdoing it

&u#e 'io#ations! ob ecti'e!not sub ecti'e

D no discussion! high#yfocused! anti(tri'ia

on#y do it if 'a#ue is

pro'en )continua##y*

8/9/2019 ISTQBCH3

26/47

$nspection is ore and +etter

entry criteriatrainingopti u checking rate

prioritising the wordsstandards

process i prove ente;it criteriaquantified esti ates of

re aining a8or faultsper page

typical re)ie*

early %nspection

mature %nspection

effecti)eness return on in)estment

1+ , 2+- un.no*n

3+ , 4+- 6 , / hrs 0 %nsp hr

/+ , 5- / , 3+ hrs 0 %nsp hr

8/9/2019 ISTQBCH3

27/47

The $nspection ProcessSoft*are

De)elopmentStage

(

(

Planning

ic.off

%n!h. Meet !it

hange#equest

Process%mpro)ement

ntry

e"t Soft*areDe)elopment

Stage

"it

8/9/2019 ISTQBCH3

28/47

8/9/2019 ISTQBCH3

29/47

Reviews: ti e and siEe deter inerate

Time

hec.ing#ate

Si e

2 hrs5

)** pages5

* pages per hour

hec.ing#ate

8/9/2019 ISTQBCH3

30/47

Review 6Thoroughness75

ordinary review - finds some faults, one major, fi them,consider the document now corrected and !"

ma or inor

inor

8/9/2019 ISTQBCH3

31/47

8/9/2019 ISTQBCH3

32/47

$nspection Thoroughness

Inspection can find deep-seated faults:# all of that type can $e corrected# $ut needs optimum chec%in& rate

8/9/2019 ISTQBCH3

33/47

8/9/2019 ISTQBCH3

34/47

Contents

Reviews and the test process

Types of review

Static analysis

8/9/2019 ISTQBCH3

35/47

#hat can static analysis do5

#emem8er9 static techniques !onot e"ecute

the co!e = for of auto ated testing

check for violations of standards

check for things which ay +e a fault

8/9/2019 ISTQBCH3

36/47

&escended fro co piler technologya co piler statically analyses code, and 6knows7 alot a+out it, e g varia+le usageI finds synta; faultsstatic analysis tools e;tend this knowledgecan find unreacha+le code, undeclared varia+les,para eter type is- atches, uncalled functions !procedures, array +ound violations, etc

8/9/2019 ISTQBCH3

37/47

&ata flow analysis

This is the study of progra varia+lesvaria+le definedJ where a value is stored into itvaria+le used where the stored value is accessedvaria+le is undefined +efore it is defined or when itgoes out of scope

+defined shou#d not be confused with dec#ared

" : y ;

%$ a < 8 T= rea!>S?

x is defined! y and , are used

a and b are used! S is defined

8/9/2019 ISTQBCH3

38/47

&ata flow analysis faults

n 9: +

rea! >"?

n 9: 1

*hile " < y !o8egin

rea! >y?

*rite> n7y?

" 9: " , n

en!

-ata f#ow anoma#y. n isre(defined without being used

-ata f#ow fau#t. y is used before it has been defined )first time around the #oop*

8/9/2019 ISTQBCH3

39/47

Control flow analysis

/ighlights:nodes not accessi+le fro start nodeinfinite loops

ultiple entry to loopswhether code is well structured, i e reduci+lewhether code confor s to a flowchart gra ar any 8u ps to undefined la+els

any la+els not 8u ped tocyclo atic co ple;ity and other etrics

8/9/2019 ISTQBCH3

40/47

Knreacha+le code e;a ple

Aacro definitions (different for different platfor s the code runs on"

%uffsiEe: )***Aail+o; a;: )***$0 %uffsiEe L Aail+o; a; T/ >

rror- ;it>&$0

8/9/2019 ISTQBCH3

41/47

Static =nalysis finds the T/ > clauseunreacha+le, so will flag a fault

8/9/2019 ISTQBCH3

42/47

Cyclo atic co ple;ity

cyclo atic co ple;ity is a easure of theco ple;ity of a flow graph

(and therefore the code that the flow graph represents"

the ore co ple; the flow graph, the greater theeasure

it can ost easily +e calculated as:

co ple;ity H nu +er of decisions M )

8/9/2019 ISTQBCH3

43/47

#hich flow graph is ost co ple;5

)

2 @

hat is the cyc#omatic comp#exity0

l l fl hinit

8/9/2019 ISTQBCH3

44/47

;a ple control flow graph

#esult : +

#ight : +

D@ A=%L more Buestions

%$ 'ns*er : orrect T=

#ight : #ight ; 1

D%$

D D@

#esult : >#ight 0 Buestions?

%$ #esult < 6+- T=

Print CpassC

LS

Print Cfail

D%$

!o

if r:r;1

en!

if

res

pass

fail

en!

Pseu!o,co!e9

8/9/2019 ISTQBCH3

45/47

?ther static etrics

lines of code ('?C"operands ! operators (/alstead s etrics"fan-in ! fan-outnesting levelsfunction calls?? etrics: inheritance tree depth, nu +er of

ethods, coupling ! cohesion

8/9/2019 ISTQBCH3

46/47

'i itations and advantages

'i itations:cannot distinguish Ffail-safeF code fro progra ing faultsor ano alies (often creates overload of spurious error

essages"does not e;ecute the code, so not related to operatingconditions

=dvantages:can find faults difficult to FseeFgives o+8ective quality assess ent of code

8/9/2019 ISTQBCH3

47/47

Su ary: Ney Points

Reviews help to find faults in develop entand test docu entation, and should +eapplied early

Types of review: infor al, walkthrough,technical 9 peer review, $nspection

Static analysis can find faults and give

infor ation a+out code without e;ecuting it