thiết kế testcase trong kiểm thử phần mềm

7/31/2019 Thit k testcase trong kim th phn mm

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MC LC

MC LC ........................................................................................................... 1DANH MC CC HNH ...................................................................................2LI NI U ....................................................................................................3TM TT NI DUNG ....................................................................................... 4CHNG 1. TNG QUAN V KIM TH PHN MM ...............................6CHNG 2. THIT K TEST CASE ...........................................................20CHNG 3. P DNG ....................................................................................41

KT LUN .......................................................................................................53TI LIU THAM KHO .................................................................................54

NHN XT CA GIO VIN HNG DN ..............................................55


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DANH MC CC HNH

Hnh 1.1 S cc cp kim th..................................................................10Hnh 2.1 Mt chng trnh nh kim th .....................................................22

Hnh 2.2 M my cho chng trnh trong Hnh 2.1...........................................26Hnh 2.3 Mt mu cho vic lit k cc lp tng ng...................................30Hnh 2.4 Cc k hiu th nguyn nhn kt qu c bn...............................34Hnh 2.5 Cc k hiu rng buc.........................................................................35Hnh 2.6 Nhng xem xt c s dng khi d theo th................................37Hnh 3.1 th nguyn nhn kt qu:.............................................................44Hnh 3.2 Bng quyt nh...................................................................................44

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LI NI U

Trong ngnh k ngh phn mm, nm 1979, c mt quy tc ni ting l: Trongmt d n lp trnh in hnh, th xp x 50% thi gian v hn 50% tng chi ph c

s dng trong kim th cc chng trnh hay h thng c pht trin. V cho

n nay, sau gn mt phn 3 th k, quy tc vn cn ng. c rt nhiu ngn

ng, h thng pht trin mi vi cc cng c tch hp cho cc lp trnh vin s dng

pht trin ngy cng linh ng. Nhng kim th vn ng vai tr ht sc quan trng

trong bt k d n pht trin phn mm no.

Rt nhiu cc gio s, ging vin tng than phin rng: Sinh vin ca

chng ta tt nghip v i lm m khng c c nhng kin thc thc t cn thit v

cch kim th mt chng trnh. Hn na, chng ta him khi c c nhng li

khuyn b ch cung cp trong cc kha hc m u v cch mt sinh vin nn lm

v kim th v g li cc bi tp ca h.

Cc tc gi ca cun sch ni ting The Art of Software Testing Ngh thutkim th phn mm, Glenford J. Myers, Tom Badgett, Todd M. Thomas, Corey

Sandler khng nh trong cun sch ca mnh rng: Hu ht cc thnh phn quan

trng trong cc th thut ca mt nh kim th chng trnh l kin thc v cch

vit cc ca kim th c hiu qu. Vic xy dng cc test case l mt nhim v rt

kh khn. c th xy dng c tp cc test case hu ch cho kim th, chng

ta cn rt nhiu kin thc v kinh nghim.

l nhng l do thc y em thc hin ti ny. Mc ch ca ti l tm

hiu nhng kin thc tng quan nht v kim th, v cch thit k test case trong

kim th phn mm. Vic thc hin ti s gip em tm hiu su hn v lnh vc

rt hp dn ny, vn dng c cc kin thc hc c th thit k c cc test

case mt cch c hiu qu v p dng vo nhng bi ton thc t.

Bn bo co c hon thnh di s ch bo tn tnh ca thy gio, ThS

Nguyn Hng Tn, s gip nhit tnh ca cc thy c trong b mn Cng ngh

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phn mm, v tt c cc bn. Em hi vng s nhn c s ng gp kin ca cc

thy c v cc bn bn bo co c hon thin hn. Nhng ng gp s l

kinh nghim qu bu cho em. V t , em c th tip tc pht trin ti ny cho

t thc tp tt nghip v n tt nghip sp ti, cng nh cho cng vic trongtng lai.

Em xin chn thnh cm n.

Sinh vin

Phm Th Trang

TM TT NI DUNG

Bn bo co c chia thnh 3 chng vi ni dung nh sau:

Chng 1: Tng quan v kim th phn mm.

Chng ny l ci nhn tng quan v kim th phn mm:

cc khi nim c bn v kim th phn mm, cc quy tc

trong kim th, v cc phng php kim th phn mm tiu

biu.

Chng 2: Thit k test case trong kim th phn mm.

Trong chng ny, em i tm hiu cc phng php thit k

test case c hiu qu. T rt ra nhn xt v u nhc

im ca tng phng php.

Chng 3: p dng.

T nhng phng php thit k test case tm hiu trong

Chng 2, em p dng xy dng tp cc test case cho

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mt bi ton c th : Thit k cc test case cho chng

trnh Tam gic.

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CHNG 1. TNG QUAN V KIM TH

PHN MM

1.1 Cc khi nim c bn v kim th phn mm

1.1.1 Kim th phn mm l g?

Kim th phn mm l qu trnh kho st mt h thng hay thnh phn di

nhng iu kin xc nh, quan st v ghi li cc kt qu, v nh gi mt kha

cnh no ca h thng hay thnh phn . (Theo Bng ch gii thut ng

chun IEEE ca Thut ng k ngh phn mm- IEEE Standard Glossary of Software

Engineering Terminology).

Kim th phn mm l qu trnh thc thi mt chng trnh vi mc ch tm

li. (Theo The Art of Software Testing Ngh thut kim th phn mm).

Kim th phn mm l hot ng kho st thc tin sn phm hay dch v

phn mm trong ng mi trng chng d nh s c trin khai nhm cung

cp cho ngi c li ch lin quan nhng thng tin v cht lng ca sn phm

hay dch v phn mm y. Mc ch ca kim th phn mm l tm ra cc li hay

khim khuyt phn mm nhm m bo hiu qu hot ng ti u ca phn mm

trong nhiu ngnh khc nhau. (TheoBch khoa ton th m Wikipedia).

C th nh ngha mt cch d hiu nh sau:Kim th phn mm l mt tin

trnh hay mt tp hp cc tin trnh c thit k m bo m ha my tnh

thc hin theo ci m chng c thit k lm, v khng thc hin bt c

th g khng mong mun. y l mt pha quan trng trong qu trnh pht trin h

thng, gip cho ngi xy dng h thng v khch hng thy c h thng mi

p ng yu cu t ra hay cha?

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1.1.2 Cc phng php kim th

C 2 phng php kim th chnh l: Kim th tnh v Kim th ng.

1.1.2.1 Kim th tnh Static testing

L phng php th phn mm i hi phi duyt li cc yu cu v cc c t

bng tay, thng qua vic s dng giy, bt kim tra logic, ln tng chi tit m

khng cn chy chng trnh. Kiu kim th ny thng c s dng bi chuyn

vin thit k ngi m vit m lnh mt mnh.

Kim th tnh cng c th c t ng ha. N s thc hin kim tra ton b

bao gm cc chng trnh c phn tch bi mt trnh thng dch hoc bin dch m

xc nhn tnh hp l v c php ca chng trnh.

1.1.2.2 Kim th ng Dynamic testing

L phng php th phn mm thng qua vic dng my chy chng trnh iu tra trng thi tc ng ca chng trnh. l kim th da trn cc ca kim

th xc nh bng s thc hin ca i tng kim th hay chy cc chng trnh.

Kim th ng kim tra cch thc hot ng ng ca m lnh, tc l kim tra s

phn ng vt l t h thng ti cc bin lun thay i theo thi gian. Trong kim th

ng, phn mm phi thc s c bin dch v chy. Kim th ng thc s bao

gm lm vic vi phn mm, nhp cc gi tr u vo v kim tra xem liu u ra c

nh mong mun hay khng. Cc phng php kim th ng gm c kim th Unit

Unit Tests, Kim th tch hp Intergration Tests, Kim th h thng System

Tests, v Kim th chp nhn sn phm Acceptance Tests.

1.1.3 Cc chin lc kim th

Ba trong s nhng chin lc kim th thng dng nht bao gm: Kim th

hp en, Kim th hp trng, v Kim th hp xm.

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1.1.3.1 Kim th hp en Black box testing

Mt trong nhng chin lc kim th quan trng l kim th hp en, hng

d liu, hay hng vo/ra. Kim th hp en xem chng trnh nh l mt hpen. Mc ch ca bn l hon ton khng quan tm v cch c x v cu trc bn

trong ca chng trnh. Thay vo , tp trung vo tm cc trng hp m chng

trnh khng thc hin theo cc c t ca n.

Theo hng tip cn ny, d liu kim tra c ly ch t cc c t.

Cc phng php kim th hp en

Phn lp tng ng Equivalence partitioning.

Phn tch gi tr bin Boundary value analysis.

Kim th mi cp All-pairs testing.

Kim th fuzz Fuzz testing.

Kim th da trn m hnh Model-based testing.

Ma trn du vt Traceability matrix.

Kim th thm d Exploratory testing.

Kim th da trn c t Specification-base testing.

Kim th da trn c t tp trung vo kim tra tnh thit thc ca phn mm

theo nhng yu cu thch hp. Do , kim th vin nhp d liu vo, v ch thy d

liu ra t i tng kim th. Mc kim th ny thng yu cu cc ca kim th trit

c cung cp cho kim th vin m khi c th xc minh l i vi d liu u

vo cho, gi tr u ra (hay cch thc hot ng) c ging vi gi tr mong mun

c xc nh trong ca kim th hay khng. Kim th da trn c t l cn

thit, nhng khng ngn chn nhng ri ro chc chn.

u, nhc im

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Kim th hp en khng c mi lin quan no ti m lnh, v kim th vin ch

rt n gin tm nim l: mt m lnh phi c li. S dng nguyn tc Hy i hi

v bn s c nhn, nhng kim th vin hp en tm ra li m nhng lp trnh

vin khng tm ra. Nhng, mt khc, ngi ta cng ni kim th hp en gingnh l i trong bng ti m khng c n vy, bi v kim th vin khng bit cc

phn mm c kim tra thc s c xy dng nh th no. l l do m c

nhiu trng hp m mt kim th vin hp en vit rt nhiu ca kim th kim

tra mt th g m ng l c th ch cn kim tra bng 1 ca kim th duy nht,

v/hoc mt s phn ca chng trnh khng c kim tra cht no.

Do vy, kim th hp en c u im ca mt s nh gi khch quan, mtkhc n li c nhc im ca thm d m.

1.1.3.2 Kim th hp trng White box testing

L mt chin lc kim th khc, tri ngc hon ton vi kim th hp en,

kim th hp trng hay kim th hng logic cho php bn kho st cu trc bn

trong ca chng trnh. Chin lc ny xut pht t d liu kim th bng s kimth tnh logic ca chng trnh. Kim th vin s truy cp vo cu trc d liu v

gii thut bn trong chng trnh (v c m lnh thc hin chng).

Cc phng php kim th hp trng

Kim th giao din lp trnh ng dng - API testing (application

programming interface): l phng php kim th ca ng dng s

dng cc API cng khai v ring t.

Bao ph m lnh Code coverage: to cc kim tra p ng mt s

tiu chun v bao ph m lnh.

Cc phng php gn li Fault injection.

Cc phng php kim th hon chuyn Mutation testing methods.

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Kim th tnh Static testing: kim th hp trng bao gm mi kim

th tnh.

Phng php kim th hp trng cng c th c s dng nh gi s hon

thnh ca mt b kim th m c to cng vi cc phng php kim th hp en.

iu ny cho php cc nhm phn mm kho st cc phn ca 1 h thng t khi c

kim tra v m bo rng nhng im chc nng quan trng nht c kim tra.

1.1.3.3 Kim th hp xm Gray box testing

Kim th hp xm i hi phi c s truy cp ti cu trc d liu v gii thutbn trong cho nhng mc ch thit k cc ca kim th, nhng l kim th mc

ngi s dng hay mc hp en. Vic thao tc ti d liu u vo v nh dng d

liu u ra l khng r rng, ging nh mt chic hp xm, bi v u vo v u

ra r rng l bn ngoi hp en m chng ta vn gi v h thng c kim tra.

S khc bit ny c bit quan trng khi qun l kim th tch hp Intergartion

testinggia 2 modun m lnh c vit bi hai chuyn vin thit k khc nhau, trong

ch giao din l c a ra kim th. Kim th hp xm c th cng bao gm

c thit k i chiu quyt nh, v d, gi tr bin hay thng bo li.

1.1.4 Cc cp kim th phn mm

Kim th phn mm gm c cc cp : Kim th n v, Kim th tch hp,

Kim th h thng v Kim th chp nhn sn phm.

Hnh 1.1 S cc cp kim th

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1.1.4.1 Kim th n v Unit test

Mt n v l mt thnh phn phn mm nh nht m ta c th kim th c.

V d, cc hm (Function), th tc (Procedure), lp (Class) hay phng thc

(Method) u c th c xem l Unit.

V Unit c chn kim tra thng c kch thc nh v chc nng hot

ng n gin, chng ta khng kh khn g trong vic t chc kim th, ghi nhn v

phn tch kt qu kim th. Nu pht hin li, vic xc nh nguyn nhn v khc

phc cng tng i d dng v ch khoanh vng trong mt n th Unit ang kim

tra. Mt nguyn l c kt t thc tin: thi gian tn cho Unit Test s c n b

bng vic tit kim rt nhiu thi gian v chi ph cho vic kim th v sa li cc

mc kim th sau .

Unit Test thng do lp trnh vin thc hin. Cng on ny cn c thc hin

cng sm cng tt trong giai on vit code v xuyn sut chu k pht trin phn

mm. Thng thng, Unit Test i hi kim th vin c kin thc v thit k v code

ca chng trnh. Mc ch ca Unit Test l bo m thng tin c x l v xut

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(khi Unit) l chnh xc, trong mi tng quan vi d liu nhp v chc nng ca

Unit. iu ny thng i hi tt c cc nhnh bn trong Unit u phi c kim tra

pht hin nhnh pht sinh li. Mt nhnh thng l mt chui cc lnh c thc

thi trong mt Unit. V d: chui cc lnh sau iu kin If v nm gia then ... else lmt nhnh. Thc t vic chn la cc nhnh n gin ha vic kim th v qut

ht Unit i hi phi c k thut, i khi phi dng thut ton chn la.

Cng vi cc mc kim th khc, Unit Test cng i hi phi chun b trc

cc ca kim th (Test case) hoc kch bn kim th (Test script), trong ch nh r

d liu u vo, cc bc thc hin v d liu u ra mong mun. Cc Test case v

Test script ny nn c gi li ti s dng.

1.1.4.2 Kim th tch hp Intergration Test

Integration test kt hp cc thnh phn ca mt ng dng v kim th nh mt

ng dng hon thnh. Trong khi Unit Test kim tra cc thnh phn v Unit ring l

th Intgration Test kt hp chng li vi nhau v kim tra s giao tip gia chng.

Hai mc tiu chnh ca Integration Test:

Pht hin li giao tip xy ra gia cc Unit.

Tch hp cc Unit n l thnh cc h thng nh (Subsystem) v cui

cng l nguyn h thng hon chnh (System) chun b cho kim th

mc h thng (System Test).

Trong Unit Test, lp trnh vin c gng pht hin li lin quan n chc nng v

cu trc ni ti ca Unit. C mt s php kim th n gin trn giao tip gia Unit

vi cc thnh phn lin quan khc, tuy nhin mi giao tip lin quan n Unit ch tht

s c kim tra y khi cc Unit tch hp vi nhau trong khi thc hin

Integration Test.

Tr mt s t ngoi l, Integration Test ch nn thc hin trn nhng Unit

c kim tra cn thn trc bng Unit Test, v tt c cc li mc Unit c

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hoc phn cng c th, c bit l cc ng dng thi gian thc, h thng phn b,

hoc h thng nhng. mc h thng, ngi kim th cng tm kim cc li,

nhng trng tm l nh gi v hot ng, thao tc, s tin cy v cc yu cu khc

lin quan n cht lng ca ton h thng.

im khc nhau then cht gia Integration Test v System Test l System Test

ch trng cc hnh vi v li trn ton h thng, cn Integration Test ch trng s giao

tip gia cc n th hoc i tng khi chng lm vic cng nhau. Thng thng ta

phi thc hin Unit Test v Integration Test bo m mi Unit v s tng tc

gia chng hot ng chnh xc trc khi thc hin System Test.

Sau khi hon thnh Integration Test, mt h thng phn mm c hnh

thnh cng vi cc thnh phn c kim tra y . Ti thi im ny, lp trnh

vin hoc kim th vin bt u kim th phn mm nh mt h thng hon chnh.

Vic lp k hoch cho System Test nn bt u t giai on hnh thnh v phn tch

cc yu cu.

System Test kim th c cc hnh vi chc nng ca phn mm ln cc yu cu

v cht lng nh tin cy, tnh tin li khi s dng, hiu nng v bo mt. Mc

kim th ny c bit thch hp cho vic pht hin li giao tip vi phn mm hoc

phn cng bn ngoi, chng hn cc li "tc nghn" (deadlock) hoc chim dng b

nh. Sau giai on System Test, phn mm thng sn sng cho khch hng hoc

ngi dng cui cng kim th chp nhn sn phm (Acceptance Test) hoc dng th

(Alpha/Beta Test).

i hi nhiu cng sc, thi gian v tnh chnh xc, khch quan, System Testthng c thc hin bi mt nhm kim th vin hon ton c lp vi nhm pht

trin d n. Bn thn System Test li gm nhiu loi kim th khc nhau, ph bin

nht gm:

Kim th chc nng (Functional Test): Bo m cc hnh vi ca h

thng tha mn ng yu cu thit k.

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Kim th hiu nng (Performance Test): Bo m ti u vic phn b

ti nguyn h thng (v d b nh) nhm t cc ch tiu nh thi gian

x l hay p ng cu truy vn...

Kim th kh nng chu ti (Stress Test hay Load Test): Bo m hthng vn hnh ng di p lc cao (v d nhiu ngi truy xut cng

lc). Stress Test tp trung vo cc trng thi ti hn, cc "im cht", cc

tnh hung bt thng nh ang giao dch th ngt kt ni (xut hin

nhiu trong kim tra thit b nh POS, ATM...)...

Kim th cu hnh (Configuration Test).

Kim th bo mt (Security Test): Bo m tnh ton vn, bo mt ca

d liu v ca h thng.

Kim th kh nng phc hi (Recovery Test): Bo m h thng c

kh nng khi phc trng thi n nh trc trong tnh hung mt ti

nguyn hoc d liu; c bit quan trng i vi cc h thng giao dch

nh ngn hng trc tuyn...

Nhn t quan im ngi dng, cc cp kim th trn rt quan trng: Chng

bo m h thng kh nng lm vic trong mi trng thc.

Lu l khng nht thit phi thc hin tt c cc loi kim th nu trn. Ty

yu cu v c trng ca tng h thng, tu kh nng v thi gian cho php ca d

n, khi lp k hoch, ngi Qun l d n s quyt nh p dng nhng loi kim th

no.

1.1.4.4 Kim th chp nhn sn phm Acceptance Test

Thng thng, sau giai on System Test l Acceptance Test, c khch hng

thc hin (hoc y quyn cho mt nhm th ba thc hin). Mc ch ca Acceptance

Test l chng minh phn mm tha mn tt c yu cu ca khch hng v khch

hng chp nhn sn phm (v tr tin thanh ton hp ng).

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Acceptance Test c ngha ht sc quan trng, mc d trong hu ht mi

trng hp, cc php kim th ca System Test v Acceptance Test gn nh tng

t, nhng bn cht v cch thc thc hin li rt khc bit.

i vi nhng sn phm dnh bn rng ri trn th trng cho nhiu ngi s

dng, thng thng s thng qua hai loi kim th gi l kim th Alpha Alpha

Testv kim th Beta Beta Test. Vi Alpha Test, ngi dng kim th phn mm

ngay ti ni pht trin phn mm, lp trnh vin s ghi nhn cc li hoc phn hi, v

ln k hoch sa cha. Vi Beta Test, phn mm s c gi ti cho ngi dng

kim th ngay trong mi trng thc, li hoc phn hi cng s gi ngc li cho lp

trnh vin sa cha.

Thc t cho thy, nu khch hng khng quan tm v khng tham gia vo qu

trnh pht trin phn mm th kt qu Acceptance Test s sai lch rt ln, mc d

phn mm tri qua tt c cc kim th trc . S sai lch ny lin quan n vic

hiu sai yu cu cng nh s mong ch ca khch hng. V d i khi mt phn mm

xut sc vt qua cc php kim th v chc nng thc hin bi nhm thc hin d

n, nhng khch hng khi kim th sau cng vn tht vng v b cc mn hnh nghonn, thao tc khng t nhin, khng theo tp qun s dng ca khch hng v.v...

Gn lin vi giai on Acceptance Test thng l mt nhm nhng dch v v

ti liu i km, ph bin nh hng dn ci t, s dng v.v... Tt c ti liu i km

phi c cp nht v kim th cht ch.

1.1.4.5 Mt s cp kim th khc

Ngoi cc cp trn, cn mt s cp kim th khc nh:

Kim th hi quy Regression Testing:

Theo chun IEEE610.12-90, kim th hi quy l s kim tra li c la chn

ca mt h thng hay thnh phn xc minh l nhng s thay i khng gy ra

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nhng hu qu khng mong mun. Trn thc t, quan nim ny l ch ra rng

phn mm m qua c cc kim tra trc vn c th c kim tra li. Beizer

nh ngha l s lp li cc kim tra ch ra rng cch hot ng ca phn mm

khng b thay i, ngoi tr ti mc nh yu cu. Hin nhin l s tha hip phic thc hin gia s m bo c a ra bi kim th hi quy mi ln thc hin

mt s thay i v nhng ti nguyn c yu cu thc hin iu .

Kim th tnh ng Correctness testing:

Tnh ng n l yu cu ti thiu ca phn mm, l mc ch ch yu ca

kim th. Kim th tnh ng s cn mt kiu ngi ng tin no , ch ra cch

hot ng ng n t cch hot ng sai lm. Kim th vin c th bit hoc khng

bit cc chi tit bn trong ca cc modun phn mm c kim th, v d lung iu

khin, lung d liu, v.v . Do , hoc l quan im hp trng, hoc l quan im

hp en c th c thc hin trong kim th phn mm.

1.1.5 Cc phng php kim th con ngi

Hai phng php kim th con ngi ch yu l Code Inspections v

Walkthroughs. Hai phng php ny bao gm mt nhm ngi c v kim tra theo

m lnh ca chng trnh. Mc tiu ca chng l tm ra li m khng g li.

MtInspection hay Walkthrough l 1 s ci tin ca phng php kim tra m

lp trnh vin c chng trnh ca h trc khi kim th n. Inspections v

Walkthroughs hiu qu hn l bi v nhng ngi khc s kim th chng trnh tt

hn chnh tc gi ca chng trnh .

Inspections/Walkthroughs v kim th bng my tnh b sung cho nhau. Hiu

qu tm li s km i nu thiu i 1 trong 2 phng php. V i vi vic sa i

chng trnh cng nn s dng cc phng php kim th ny cng nh cc k thut

kim th hi quy.

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1.1.5.1 Tng duyt Walkthrough

Walkthrough l mt thut ng m t s xem xt k lng ca mt qu trnh

mc tru tng trong nh thit k hay lp trnh vin lnh o cc thnh vin trongnhm v nhng ngi c quan tm khc thng qua mt sn phm phn mm, v

nhng ngi tham gia t cu hi, v ghi ch nhng li c th c, s vi phm cc

chun pht trin v cc vn khc. Walkthrough m lnh l 1 tp cc th tc v cc

cng ngh d li cho vic c nhm m lnh. Trong mt Walkthrough, nhm cc nh

pht trin vi 3 hoc 4 thnh vin l tt nht thc hin xt duyt li. Ch 1 trong

cc thnh vin l tc gi ca chng trnh.

Mt u im khc ca walkthroughs, hiu qu trong chi ph g li, l 1 thc t

m khi mt li c tm thy, n thng c nh v chnh xc trong m lnh. Thm

vo , phng php ny thng tm ra 1 tp cc li, cho php sau cc li c

sa tt c vi nhau. Mt khc, kim th da trn my tnh,ch tm ra triu chng ca

li (chng trnh khng kt thc hoc a ra kt qu v ngha), v cc li thng

c tm ra v sa ln lt tng li mt.

1.1.5.2 Thanh tra m ngun Code Inspection

Thanh tra m ngun l 1 tp hp cc th tc v cc k thut d li cho vic c

cc nhm m lnh. Mt nhm kim duyt thng gm 4 ngi. Mt trong s

ng vai tr l ngi iu tit mt lp trnh vin lo luyn v khng c l tc gi

ca chng trnh v phi khng quen vi cc chi tit ca chng trnh. Ngi iu

tit c nhim v: phn phi nguyn liu v lp lch cho cc bui kim duyt, ch o

phin lm vic, ghi li tt c cc li c tm thy v m bo l cc li sau c

sa. Thnh vin th hai l mt lp trnh vin. Cc thnh vin cn li trong nhm

thng l nh thit k ca chng trnh ( nu nh thit k khc lp trnh vin) v mt

chuyn vin kim th.

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1.2 Nguyn tc kim th phn mm

kim th t hiu qu th khi tin hnh kim th phn mm cn phi tun

th mt s quy tc sau:

Quy tc 1: Mt phn quan trng ca 1 ca kim th l nh ngha ca u ra hay

kt qu mong mun.

Quy tc 2: Lp trnh vin nn trnh t kim tra chng trnh ca mnh.

Quy tc 3: Nhm lp trnh khng nn kim th chng trnh ca chnh h.

Quy tc 4: Kim tra thu o mi kt qu ca mi kim tra.

Quy tc 5: Cc ca kim th phi c vit cho cc trng thi u vo khng hp

l v khng mong mun, cng nh cho cc u vo hp l v mong

mun.

Quy tc 6: Kho st 1 chng trnh xem liu chng trnh c thc hin ci m

n cn thc hin ch l 1 phn, phn cn li l xem liu chng trnh

c thc hin ci m n khng cn phi thc hin hay khng.

Quy tc 7: Trnh cc ca kim th bng qu tr khi chng trnh thc s l 1

chng trnh bng qu.

Quy tc 8: Khng d kin kt qu ca kim th theo gi thit ngm l khng tm

thy li.

Quy tc 9: Xc sut tn ti li trong 1 on chng trnh l tng ng vi s li

tm thy trong on .

Quy tc 10: Kim th l 1 nhim v cc k sng to v c tnh th thch tr tu.

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CHNG 2. THIT K TEST CASE

2.1 Khi nim

Thit k test case trong kim th phn mm l qu trnh xy dng cc phng

php kim th c th pht hin li, sai st, khuyt im ca phn mm xy dng

phn mm t tiu chun.

2.2 Vai tr ca thit k test case

To ra cc ca kim th tt nht c kh nng pht hin ra li, sai st ca

phn mm mt cch nhiu nht.

To ra cc ca kim th c chi ph r nht, ng thi tn t thi gian v

cng sc nht.

2.3 Quy trnh thit k test case

Mt trong nhng l do quan trng nht trong kim th chng trnh l thit k

v to ra cc ca kim th - cc Test case c hiu qu. Vi nhng rng buc v thi

gian v chi ph cho, th vn then cht ca kim th tr thnh:

Tp con no ca tt c ca kim th c th c kh nng tm ra nhiu li nht?

Thng thng, phng php km hiu qu nht l kim tra tt c u vo ngu

nhin qu trnh kim th mt chng trnh bng vic chn ngu nhin mt tp con

cc gi tr u vo c th. V mt kh nng tm ra nhiu li nht, tp hp cc ca kim

th c chn ngu nhin c rt t c hi l tp hp ti u hay gn ti u. Sau y l

mt s phng php chn ra mt tp d liu kim th mt cch thng minh.

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kim th hp en v kim th hp trng mt cch thu o l khng th. Do

, mt chin lc kim th hp l l chin lc c th kt hp sc mnh ca c hai

phng php trn: Pht trin 1 cuc kim th nghim ngt va bng vic s dng cc

phng php thit k ca kim th hng hp en no v sau b sung thmnhng ca kim th ny bng vic kho st tnh logic ca chng trnh, s dng

phng php hp trng.

Nhng chin lc kt hp bao gm:

Hp en Hp trng1. Phn lp tng ng

2. Phn tch gi tr bin3. th nguyn nhn kt qu

4. on li

1. Bao ph cu lnh

2. Bao ph quyt nh3. Bao ph iu kin

4. Bao ph iu kin quyt nh

5. Bao ph a iu kin.

Mi phng php c nhng u im cng nh khuyt im ring, do c

c tp cc ca kim th ti u, chng ta cn kt hp hu ht cc phng php. Quy

trnh thit k cc ca kim th s bt u bng vic pht trin cc ca kim th s dngphng php hp en v sau pht trin b sung cc ca kim th cn thit vi

phng php hp trng.

2.3.1 Kim th hp trng - Kim th bao ph logic

Kim th hp trng c lin quan ti mc m cc ca kim th thc hin hay

bao ph tnh logic (m ngun) ca chng trnh. Kim th hp trng c bn l victhc hin mi ng i trong chng trnh, nhng vic kim th y ng i l

mt mc ch khng thc t cho mt chng trnh vi cc vng lp. Cc tiu chun

trong kim th bao ph logic gm c:

2.3.1.1 Bao ph cu lnh Statement Coverage

T tng: Thc hin mi cu lnh trong chng trnh t nht 1 ln.

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Xt v d vi on m lnh JAVA sau:

public void foo (int a, int b, int x){

if (a>1 && b==0) {

x=x/a;}

if (a==2||x>1){

x=x+1;

}

}

Hnh 2.1 Mt chng trnh nh kim th

Bn c th thc hin mi cu lnh bng vic vit 1 ca kim th n i qua

ng ace. Tc l, bng vic t A=2, B=0 v X=3 ti im a, mi cu lnh s c

thc hin 1 ln (thc t, X c th c gn bt k gi tr no).

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Thng tiu chun ny kh km. V d, c l nu quyt nh u tin l php or

ch khng phi php andth li ny s khng c pht hin. Hay nu quyt nh

th hai m bt u vi x>0, li ny cng s khng c tm ra. Cng vy, c 1

ng i qua chng trnh m x khng thay i (ng i abd). Nu y l 1li, th li ny c th khng tm ra. Hay ni cch khc, tiu chun bao ph cu lnh

qu yu n ni m n thng l v ch.

2.3.1.2 Bao ph quyt nh Decision coverage

T tng: Vit cc ca kim th m mi quyt nh c kt lun ng hay sai

t nht 1 ln. Ni cch khc, mi hng phn nhnh phi c xem xt k lng t

nht 1 ln.

Cc v d v cu lnh r nhnh hay quyt nh l cc cu lnh switch, do-while,

v if-else. Cc cu lnh a ng GOTO thng s dng trong mt s ngn ng lp

trnh nh FORTRAN.

Bao ph quyt nh thng tha mn bao ph cu lnh. V mi cu lnh l trn

s bt ngun mt ng i ph no hoc l t 1 cu lnh r nhnh hoc l t im

vo ca chng trnh, mi cu lnh phi c thc hin nu mi quyt nh r nhnh

c thc hin. Tuy nhin, c t nht 3 ngoi l:

Nhng chng trnh khng c quyt nh.

Nhng chng trnh hay thng trnh con/phng thc vi nhiu im

vo. Mt cu lnh cho c th c thc hin nu v ch nu chngtrnh c nhp vo ti 1 im u vo ring.

Cc cu lnh bn trong cc ON-unit. Vic i qua mi hng r nhnh s

l khng nht thit lm cho tt c cc ON-unit c thc thi.

V chng ta thy rng bao ph cu lnh l iu kin cn thit, nn mt chin

lc tt hn l bao ph quyt nh nn c nh ngha bao hm c bao ph cu

lnh. Do , bao ph quyt nh yu cu mi quyt nh phi c kt lun ng hoc

sai, v mi cu lnh phi c thc hin t nht 1 ln.

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Phng php ny ch xem xt nhng quyt nh hay nhng s phn nhnh 2

ng v phi c sa i cho nhng chng trnh c cha nhng quyt nh a

ng. V d, cc chng trnh JAVA c cha cc lnh select (case), cc chng

trnh FORTRAN cha cc lnh s hc (ba ng) ifhoc cc lnh tnh ton hay shc GOTO, v cc chng trnh COBOL cha cc lnh GOTO bin i hay cc lnh

GO-TO-DEPENDING-ON (cc lnh goto ph thuc). Vi nhng chng trnh nh

vy, tiu chun ny ang s dng mi kt lun c th ca tt c cc quyt nh t nht

1 ln v gi mi im vo ti chng trnh hay thng trnh con t nht 1 ln.

Trong hnh 2.1, bao ph quyt nh c th t c bi t nht 2 ca kim th

bao ph cc ng ace v abdhoc acdv abe. Nu chng ta chn kh nng th hai,th 2 u vo test-case lA=3, B=0, X=3 vA=2, B=1, X=1.

Bao ph quyt nh l 1 tiu chun mnh hn bao ph cu lnh, nhng vn kh

yu. V d, ch c 50% c hi l chng ta s tm ra con ng trong x khng b

thay i (v d, ch khi bn chn kh nng th nht). Nu quyt nh th hai b li

(nu nh ng l phi ni lx1), li ny s khng c pht hin bng

2 ca kim th trong v d trc.

2.3.1.3 Bao ph iu kin Condition coverage

T tng: Vit cc ca kim th m bo rng mi iu kin trong mt

quyt nh m nhn tt c cc kt qu c th t nht mt ln.

V vy, nh vi bao ph quyt nh, th bao ph iu kin khng phi lun lundn ti vic thc thi mi cu lnh. Thm vo , trong tiu chun bao ph iu kin,

mi im vo chng trnh hay thng trnh con, cng nh cc ON-unit, c gi t

nht 1 ln. V d, cu lnh r nhnh do k=0 to 50 while (j+k


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Hnh 2.1 c 4 iu kin:A>1, B=0, A=2, X>1. Do cc ca kim th y l

cn thit thc y nhng trng thi mA>1, A1, X


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2.3.1.4 Bao ph quyt nh/iu kin Decision/condition coverage

T tng: Thc hin cc ca kim th m mi iu kin trong 1 quyt nh

thc hin trn tt c cc kt qu c th t nht 1 ln, v mi im vo c gi t nht1 ln.

im yu ca bao ph quyt nh/iu kin l mc d xem ra n c th s dng

tt c cc kt qu ca tt c cc iu kin, nhng thng khng phi vy v nhng

iu kin chc chn cn cc iu kin khc.

Hnh 2.2 M my cho chng trnh trong Hnh 2.1

Biu tin trnh trong hnh 2.2 l cch 1 trnh bin dich to ra m my cho

chng trnh trong Hnh 2.1. Cc quyt nh a iu kin trong chng trnh ngun

b chia thnh cc quyt nh v cc nhnh ring v hu ht cc my khng c

ch to c th thc hin cc quyt nh a iu kin. Khi 1 bao ph kim th t

m hn xut hin l vic s dng tt c cc kt qu c th ca mi quyt nh gc.

Hai ca kim th bao ph quyt nh trc khng lm c iu ny; chng khng th

s dng kt qufalse ca quyt nh H v kt qu true ca quyt nh K.

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L do, nh c ch ra trong hnh 2.2, l nhng kt qu ca cc iu kin

trong cc biu thc andv orc th cn tr hay ngn chn vic c lng cc quyt

nh khc. V d, nu 1 iu kin andl sai, khng cn kim tra cc iu kin tip

theo trong biu thc. Tng t nh vy, nu 1 iu kin orl ng th cng khngcn kim tra cc iu kin cn li. Do , cc li trong biu thc logic khng phi lc

no cng c pht hin bng cc tiu chun bao ph iu kin v bao ph quyt

nh/iu kin.

2.3.1.5 Bao ph a iu kin Multiple condition coverage

T tng: Vit cc ca kim th m tt c nhng s kt hp ca cc kt qu

iu kin c th trong mi quyt nh, v tt c cc im vo phi c gi t nht 1

ln.

V d, xt chui m lnh sau:

NOTFOUND = TRUE;

DO I=1 TO TABSIZE WHILE (NOTFOUND); /*SEARCH TABLE*/

searching logic;

END;

Bn tnh hung kim th l:

1. ITABSIZEv NOTFOUND c gi tr sai (mc vo l ci cui cng

trong bng).

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D nhn thy l tp hp cc ca kim th tha mn tiu chun a iu kin cng

tha mn cc tiu chun bao ph quyt nh, bao ph iu kin v bao ph quyt

nh/iu kin.

Quay li hnh 2.1, cc ca kim th phi bao ph 8 s kt hp:

1. A>1, B= 0

2. A>1, B0

3. A


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If (x==y&&length(z)==0&&FLAG) {

J=1;}

Else {

I=1;}

Trong trng hp cc vng lp, s lng cc ca kim th c yu cu bi tiu

chun a iu kin thng t hn nhiu s lng ng i.

Tm li, i vi nhng chng trnh ch cha 1 iu kin trn 1 quyt nh, th

1 tiu chun kim th nh nht l mt s lng cc ca kim th (1) gi tt c

cc kt qu ca mi quyt nh t nht 1 ln v (2) gi mi im ca mc vo (nh l

im vo hay ON-unit) t nht 1 ln, m bo l tt c cc cu lnh c thc hin

t nht 1 ln. i vi nhng chng trnh cha cc quyt nh c a iu kin th tiu

chun ti thiu l s lng cc ca kim th gi tt c nhng s kt hp c th

ca cc kt qu iu kin trong mi quyt nh, v tt c cc im vo ca chng

trnh t nht 1 ln.

2.3.2 Kim th hp en

2.3.2.1 Phn lp tng ng Equivalence Patitioning

Phn lp tng ng l mt phng php kim th hp en chia min u vo

ca mt chng trnh thnh cc lp d liu, t suy dn ra cc ca kim th. Phng

php ny c gng xc nh ra mt ca kim th m lm l ra mt lp li, do lm

gim tng s cc trng hp kim th phi c xy dng.

Thit k ca kim th cho phn lp tng ng da trn s nh gi v cc lp

tng ng vi mt iu kin vo. Lp tng ng biu th cho tp cc trng thi

hp l hay khng hp l i vi iu kin vo.

Mt cch xc nh tp con ny l nhn ra rng 1 ca kim th c la chn

tt cng nn c 2 c tnh khc:

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1. Gim thiu s lng cc ca kim th khc m phi c pht trin hon

thnh mc tiu nh ca kim th hp l.

2. Bao ph mt tp rt ln cc ca kim th c th khc. Tc l, n ni cho

chng ta mt th g v s c mt hay vng mt ca nhng li qua tp gi

tr u vo c th.

Thit k Test-case bng phn lp tng ng tin hnh theo 2 bc:

(1). Xc nh cc lp tng ng v

(2). Xc nh cc ca kim th.

Xc nh cc lp tng ng

Cc lp tng ng c xc nh bng bng cch ly mi trng thi u vo

(thng l 1 cu hay 1 cm t trong c t) v phn chia n thnh 2 hay nhiu nhm

(c th s dng bng 2.3 lit k cc lp tng ng).

Hnh 2.3 Mt mu cho vic lit k cc lp tng ng

iu kin bn ngoi Cc lp tng nghp l

Cc lp tng ngkhng hp l

Ch l hai kiu lp tng ng c xc nh: lp tng ng hp l m

t cc u vo hp l ca chng trnh, v lp tng ng khng hp l m t tt c

cc trng thi c th khc ca iu kin (v d, cc gi tr u vo khng ng). Vi 1

u vo hay iu kin bn ngoi cho, vic xc nh cc lp tng ng hu nh

l 1 quy trnh mang tnh kinh nghim. xc nh cc lp tng ng c c th p

dng tp cc nguyn tc di y:

1. Nu 1 trng thi u vo nh r gii hn ca cc gi tr, xc nh 1 lp

tng ng hp l v 2 lp tng ng khng hp l.

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2. Nu 1 trng thi u vo xc nh s gi tr, xc nh 1 lp tng ng

hp l v 2 lp tng ng bt hp l.

3. Nu 1 trng thi u vo ch nh tp cc gi tr u vo v chng trnh s

dng mi gi tr l khc nhau, xc nh 1 lp tng ng hp l cho miloi v 1 lp tng ng khng hp l.

4. Nu 1 trng thi u vo ch nh mt tnh hung chc chn must be,

xc nh 1 lp tng ng hp l v 1 lp tng ng khng hp l.

Nu c bt k l do no tin rng chng trnh khng x l cc phn t trong

cng 1 lp l nh nhau, th hy chia lp tng ng thnh cc lp tng ng

nh hn.

Xc nh cc ca kim th

Vi cc lp tng ng xc nh c bc trn, bc th hai l s dng

cc lp tng ng xc nh cc ca kim th. Qu trnh ny nh sau:

1. Gn 1 s duy nht cho mi lp tng ng.

2. Cho n khi tt c cc lp tng ng hp l c bao ph bi (hp nht

thnh) cc ca kim th, vit 1 ca kim th mi bao ph cng nhiu cc lp

tng ng cha c bao ph cng tt.

3. Cho n khi cc ca kim th ca bn bao ph tt c cc lp tng ng

khng hp l, vit 1 ca kim th m bao ph mt v ch mt trong cc lp

tng ng khng hp l cha c bao ph.

4. L do m mi ca kim th ring bao ph cc trng hp khng hp l l vcc kim tra u vo khng ng no che giu hoc thay th cc kim tra

u vo khng ng khc.

Mc d vic phn lp tng ng l rt tt khi la chn ngu nhin cc ca

kim th, nhng n vn c nhng thiu st. V d, n b qua cc kiu test case c

li no . Hai phng php tip theo, phn tch gi tr bin v th nguyn nhn

kt qu , bao ph c nhiu nhng thiu st ny.

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2.3.2.2 Phn tch gi tr bin Boundary Value Analysis

Kinh nghim cho thy cc ca kim th m kho st t m cc iu kin bin c

t l phn trm cao hn cc ca kim th khc. Cc iu kin bin l nhng iu kinm cc tnh hung ngay ti, trn v di cc cnh ca cc lp tng ng u vo

v cc lp tng ng u ra. Phn tch cc gi tr bin l phng php thit k ca

kim th b sung thm cho phn lp tng ng, nhng khc vi phn lp tng

ng 2 kha cnh:

1. Phn tch gi tr bin khng la chn phn t bt k no trong 1 lp tng

ng l in hnh, m n yu cu l 1 hay nhiu phn t c la chn

nh vy m mi cnh ca lp tng ng chnh l i tng kim tra.

2. Ngoi vic ch tp trung ch vo cc trng thi u vo (khng gian u

vo), cc ca kim th cng nhn c bng vic xem xt khng gian kt qu

(cc lp tng ng u ra).

Phn tch gi tr bin yu cu c sng to v lng chuyn mn ha nht nh

v n l mt qu trnh mang tnh kinh nghim rt cao. Tuy nhin, c mt s quy tcchung nh sau:

1. Nu 1 trng thi u vo nh r gii hn ca cc gi tr, hy vit cc ca

kim th cho cc gi tr cui ca gii hn, v cc ca kim th u vo khng

hp l cho cc trng hp va ra ngoi phm vi.

2. Nu 1 trng thi u vo nh r s lng gi tr, hy vit cc ca kim th

cho con s ln nht v nh nht ca cc gi tr v mt gi tr trn, mt gi tr

di nhng gi tr ny.

3. S dng quy tc 1 cho mi trng thi u vo. V d, nu 1 chng trnh

tnh ton s khu tr FICA hng thng v nu mc ti thiu l 0.00$, v ti

a l 1,165.25$, hy vit cc ca kim th m khu tr 0.00$ v 1,165.25,

khu tr m v khu tr ln hn 1,165.25$. Ch l vic xem xt gii hn

ca khng gian kt qu l quan trng v khng phi lc no cc bin ca

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min u vo cng m t cng mt tp s kin nh bin ca gii hn u ra

(v d, xt chng trnh con tnh SIN). Ngoi ra, khng phi lc no cng c

th to ra 1 kt qu bn ngoi gii hn u ra, nhng tuy nhin rt ng

xem xt tim n .

4. S dng nguyn tc 2 cho mi trng thi u ra.

5. Nu u vo hay u ra ca 1 chng trnh l tp c sp th t ( v d,1

file tun t hay 1 danh sch nh tuyn hay 1 bng) tp trung ch vo cc

phn t u tin v cui cng ca tp hp.

6. S dng s kho lo ca bn tm cc iu kin bin.

2.3.2.3 th nguyn nhn kt qu - Cause & Effect Graphing

Mt yu im ca phn tch gi tr bin v phn lp tng ng l chng

khng kho st s kt hp ca cc trng hp u vo. Vic kim tra s kt hp u

vo khng phi l mt nhim v n gin bi v nu bn phn lp tng ng cc

trng thi u vo, th s lng s kt hp thng l rt ln. Nu bn khng c cch

la chn c h thng mt tp con cc trng thi u vo, c l bn s chn ra mt tp

ty hng cc iu kin, iu ny c th dn ti vic kim th khng c hiu qu.

th nguyn nhn kt qu h tr trong vic la chn mt cch c h thng

tp cc ca kim th c hiu qu cao. N c tc ng c li nh hng ti vic ch ra

tnh trng cha y v nhp nhng trong c t. N cung cp c cch biu din

chnh xc cho cc iu kin logic v hnh ng tng ng

Qu trnh di y c s dng xy dng c cc test case:

1. c t c chia thnh cc phn c th thc hin c. iu ny l cn

thit bi v th nguyn nhn kt qu tr nn kh s dng khi c s

dng trn nhng c t ln.

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2. Nguyn nhn v kt qu trong cc c t c nhn bit. Mt nguyn nhn

l mt trng thi u vo nht nh hay mt lp tng ng ca cc trng

thi u vo. Mt kt qu l mt trng thi u ra hay 1 s bin i h thng

(kt qu cn li m 1 u vo c trng thi ca 1 chng trnh hay hthng). Bn nhn bit nguyn nhn v kt qu bng vic c tng t ca c

t v gch chn cc t hoc cm t m t nguyn nhn v kt qu. Khi c

nhn bit, mi nguyn nhn v kt qu c gn cho 1 s duy nht.

3. Xy dng th nguyn nhn kt qu bng cch pht trin v bin i ni

dung ng ngha ca c t thnh th Boolean ni gia nguyn nhn v kt

qu.

4. th c c din gii vi cc rng buc m t nhng s kt hp ca

nguyn nhn v/hoc kt qu l khng th v cc rng buc ng ngha v

mi trng.

5. Bng vic d theo cc iu kin trng thi trong th mt cch cn thn,

bn chuyn i th thnh mt bng quyt nh mc vo gii hn. Mi ct

trong bng m t mt ca kim th.

6. Cc ct trong bng quyt nh c chuyn thnh cc ca kim th.

K hiu c bn cho th c ch ra trong hnh 2.4. Tng tng mi nt c

gi tr l 0 hoc 1; 0 m t trng thi vng mt v 1 m t trng thi c mt. Hm

ng nht ni l nu a l 1 th b l 1; ngc li, b l 0. Hm notl ni nu a l 1 th

b l 0; ngc li th b l 1. Hm orkhng nh rng nu a hoc b hoc c l 1, th dl

1; ngc li dl 0. Hm andkhng nh nu c a v b l 1 th c l 1; ngc li c l 0.

Hai hm orv andc php c s lng u vo bt k.

Hnh 2.4 Cc k hiu th nguyn nhn kt qu c bn

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Trong hu ht cc chng trnh, s kt hp no ca mt s nguyn nhn l

khng th bi v l do ng ngha v mi trng (v d, mt k t khng th ng thi

va l A va l B). khi , ta s dng k hiu trong Hnh 2.5. Rng buc E

(Exclude loi tr) khng nh rng ti a, ch c hoc a hoc b c th l 1 (a v b

khng th ng thi l 1). Rng buc I (Include bao hm) khng nh t nht mt

trong a, b hoc cphi lun lun l 1 (a, b hoc c khng th ng thi l 0). Rng

buc O (Only ch mt) khng nh mt v ch mt hoc a hoc b phi l 1. Rng

buc R (Request yu cu) khng nh rng khi a l 1, th b phi l 1 (v d, khng

th c trng hp a l 1, cn b l 0). Rng buc M (Mask mt n) khng nh lnu kt qu a l 1, kt qu b s bt buc phi l 0.

Hnh 2.5 Cc k hiu rng buc

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Bc tip theo l to bng quyt nh mc vo gii hn limited-entry decision

table. Tng t vi cc bng quyt nh, th nguyn nhn chnh l cc iu kin v

kt qu chnh l cc hnh ng. Quy trnh c s dng l nh sau:

1. Chn mt kt qu l trng thi c mt (1).

2. Ln ngc tr li th, tm tt c nhng s kt hp ca cc nguyn nhn

(i tng cho cc rng buc) m s thit lp kt qu ny thnh 1.

3. To mt ct trong bng quyt nh cho mi s kt hp nguyn nhn.

4. Vi mi s kt hp, hy quy nh trng thi ca tt c cc kt qu khc v

t chng vo mi ct.

Trong khi biu din bc 2, cn quan tm cc vn sau:

1. Khi ln ngc tr li qua mt nt orm u ra ca n l 1, khng bao gi

thit lp nhiu hn 1 u vo cho nt orl 1 mt cch ng thi. iu ny

c gi l path sensitizing lm nhy ng i. Mc tiu ca n l

ngn chn d li tht bi v mt nguyn nhn che i mt nguyn nhn khc.

2. Khi ln ngc tr li qua mt nt andm u ra ca n l 0, d nhin, phi

lit k tt c cc s kt hp u vo dn ti u ra 0. Tuy nhin, nu bn

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ang kho st trng thi m 1 u ra l 0 v mt hay nhiu u ra khc l 1,

th khng nht thit phi lit k tt c cc iu kin m di iu kin

cc u vo khc c th l 1.

3. Khi ln ngc tr li qua mt nt andm u ra ca n l l 0, ch cn lit

k 1 iu kin trong tt c u vo bng 0. (Nu nt and chnh gia

ca th nh vy th tt c cc u vo ca n xut pht t cc nt trung

gian khc, c th c qu nhiu trng thi m trong trng thi tt c cc

u vo ca n bng 0.)

Hnh 2.6 Nhng xem xtc s dng khi d theo th

Nu x=1, khng quan tm v

trng hp a=b=1 (s xem xt th

1)

Nu x=0, lit k tt c cc trng

hp trong a=b=0.

Nux =1, lit k tt c cc trng

hp trong a=b=c=1.

Nu x=0, bao gm ch 1 trng

hp m a=b=c=0 (s xem xt 3).

i vi cc trng thi m abc l

001, 010, 100, 011, 101 v 110 ,

bao gm ch 1 trng hp mi

trng thi (s xem xt 2).Nhng s xem xt ny c th xut hin tht thng, nhng chng c mt mc

ch rt quan trng: gim bt cc kt qu c kt hp ca th. Chng lit k

cc trng hp m hng v cc ca kim th t c li. Nu cc ca kim th t c li

khng c lit k, mt th nguyn nhn kt qu ln s to ra mt s lng ca

kim th cc k ln. Nu s lng cc ca kim th trn thc t l qu ln, bn s

chn ra 1 tp con no , nhng khng m bo l cc ca kim th t c li s l

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nhng ca kim th c lit k. Do , tt hn ht l lit k chng trong sut qu

trnh phn tch ca th.

NHN XT

V th nguyn nhn kt qu l phng php to cc ca kim th c h

thng m t s kt hp ca cc iu kin. S thay i s l 1 s la chn kt hp

khng th d tnh trc, nhng khi thc hin nh vy, c v nh bn s b st nhiu

ca kim th th v c xc nh bng th nguyn nhn kt qu .

V v th nguyn nhn kt qu yu cu chuyn mt c t thnh mt mnglogic Boolean, n cung cp mt trin vng khc v s hiu bit su sc hn na v

c t. Trn thc t, s pht trin ca 1 th nguyn nhn kt qu l cch hay

khm ph s m h v cha y trong cc c t.

Mc d vic v th nguyn nhn kt qu to ra tp cc ca kim th hu

dng, nhng thng thng n khng to ra tt c cc ca kim th hu dng m c th

c nhn bit. Ngoi ra, th nguyn nhn kt qu khng kho st tha ng cc

iu kin gii hn. D nhin, bn c th c gng bao ph cc iu kin gii hn trong

sut qu trnh.

Tuy nhin, vn trong vic thc hin iu ny l n lm cho th rt phc

tp v dn ti s lng rt ln cc ca kim th. V th, tt nht l xt 1 s phn tch

gi tr gii hn tch ri nhau.

V th nguyn nhn kt qu lm chng ta mt thi gian trong vic chn ccgi tr c th cho cc ton hng, nn cc iu kin gii hn c th b pha trn thnh

cc ca kim th xut pht t th nguyn nhn kt qu. V vy, chng ta t c

mt tp cc ca kim th nh nhng hiu qu m tha mn c 2 mc tiu.

Ch l vic v th nguyn nhn kt qu ph hp vi mt s quy tc trong

Chng 1. Vic xc nh u ra mong i cho mi ca kim th l mt phn c hu

ca k thut (mi ct trong bng quyt nh biu th cc kt qu c mong i).

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Cng ch l n khuyn khch chng ta tm kim cc kt qu c tc dng khng

mong mun.

Kha cnh kh nht ca k thut ny l qu trnh chuyn i th thnh bng

quyt nh. Qu trnh ny c tnh thut ton, tc l bn c th t ng ha n bng

vic vit 1 chng trnh. Trn th trng c mt vi chng trnh thng mi tn

ti gip cho qu trnh chuyn i ny.

2.3.2.4 on li Error Guessing

Mt k thut thit k test-case khc l error guessing on li. Tester ca cho 1 chng trnh c bit, h phng on, c bng trc gic v kinh nghim,

cc loi li c th v sau vit cc ca kim th a ra cc li .

Tht kh a ra mt quy trnh cho k thut on li v n l mt quy trnh c

tnh trc gic cao v khng th d on trc. tng c bn l lit k mt danh

sch cc li c th hay cc trng hp d xy ra li v sau vit cc ca kim th

da trn danh sch . Mt tng khc xc nh cc ca kim th c lin i vi

cc gi nh m lp trnh vin c th thc hin khi c c t (tc l, nhng th b

b st khi c t, hoc l do tnh c, hoc l v ngi vit c cm gic nhng c t

l r rng). Ni cch khc, bn lit k nhng trng hp c bit m c th

b b st khi chng trnh c thit k.

2.3.3 Chin lc

Cc phng php thit k test-case c tho lun c th c kt hp thnh

mt chin lc ton din. V mi phng php c th ng gp 1 tp ring cc ca

kim th hu dng, nhng khng ci no trong s chng t n ng gp mt tp trn

vn cc cc ca kim th. Chin lc hp l nh sau:

1. Nu c t c cha s kt hp ca cc iu kin u vo, hy bt u vi

vic v th nguyn nhn kt qu.

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2. Trong trng hp bt k, s dng phng php phn tch gi tr bin. Hy

nh rng y l mt s phn tch ca cc bin u vo v u ra. Phng

php phn tch gi tr bin mang li mt tp cc iu kin kim tra b sung,

v rt nhiu hay ton b cc iu kin ny c th c hp nht thnh cckim th nguyn nhn kt qu.

3. Xc nh cc lp tng ng hp l v khng hp l cho u vo v u

ra, v b sung cc ca kim th c xc nh trn nu cn thit.

4. S dng k thut on li thm cc ca kim th thm vo.

5. Kho st tnh logic ca chng trnh lin quan n tp cc ca kim th. Sdng tiu chun bao ph quyt nh, bao ph iu kin, bao ph quyt

nh/iu kin, hay bao ph a iu kin ( trong bao ph a iu kin l

c s dng nhiu nht ). Nu tiu chun bao ph khng t c bi cc

ca kim th c xc nh trong bn bc trc, v nu vic t c tiu

chun l khng th ( tc l, nhng s kt hp chc chn ca cc iu kin c

th l khng th to v bn cht ca chng trnh), hy thm vo cc ca kim

th c kh nng lm cho tha mn tiu chun.

Tuy vic s dng chin lc ny s khng m bo rng tt c cc li s c

tm thy, nhng n c xc minh l i din cho mt s tha thun hp l.

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CHNG 3. P DNG

T nhng phng php thit k test case tm hiu trn, em vn dngchng vo thit k test case cho chng trnh Tam gic.

3.1 c t

Chng trnh c vo 3 gi tr nguyn t hp thoi vo. Ba gi tr ny tng

ng vi chiu di 3 cnh ca 1 tam gic. Chng trnh hin th 1 thng ip cho bit

tam gic l tam gic thng, cn, hay u.

Ba gi tr nhp vo tha mn l 3 cnh ca mt tam gic khi v ch khi c 3 s

u l s nguyn dng, v tng ca 2 s bt k trong 3 s phi ln hn s th 3. Khi

, mt tam gic u l tam gic c 3 cnh bng nhau, tam gic cn l tam gic c 2

trong 3 cnh bng nhau, v tam gic thng th c 3 cnh khc nhau.

M lnh ca chng trnh:

unit main;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,

Forms, Dialogs, StdCtrls, ExtCtrls;

type

TMainForm = class(TForm)AEdit: TLabeledEdit;

BEdit: TLabeledEdit;

CEdit: TLabeledEdit;

btnTest: TButton;

procedurebtnTestClick(Sender: TObject);

private

{ Private declarations }

public

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{ Public declarations }

end;

var

MainForm: TMainForm;

implementation

{$R *.dfm}

Procedure TMainForm.btnTestClick(Sender: TObject);

var

a, b, c: Integer;

begin

try

a := StrToInt(AEdit.Text);

b := StrToInt(BEdit.Text);

c := StrToInt(CEdit.Text);

if (a < 0) Or (b < 0) Or (c < 0) then

ShowMessage('3 canh A, B, C khong thoa man la 3

canh cua mot tam giac.')

else

if (a + b > c) And (a + c > b) And (b + c > a) then

beginif (a = b) And (b = c) then

ShowMessage('3 canh A, B, C lap thanh mot

tam giac deu.')

else

if (a=b) Or (b=c) Or (c=b) then

ShowMessage('3 canh A, B, C lap

thanh mot tam giac can.')

else

ShowMessage('3 canh A, B, C lap

thanh mot tam giac thuong.');

end

else

ShowMessage('3 canh A, B, C khong thoa man

la 3 canh cua mot tam giac.');

except

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ShowMessage('Loi dinh dang du lieu. De nghi ban xem

va nhap lai.');

end;

end;

end.

3.2 Thit k test case

p dng chin lc kim th trnh by trong Chng 2, cc ca kim th

c xy dng nh sau:

3.2.1 V th nguyn nhn kt qu

Do c t c s kt hp u vo nn trc tin, p dng phng php v th

nguyn nhn kt qu.

Nguyn nhn l:

1. C 3 gi tr nhp vo u l s nguyn dng.

2. Tng 2 s bt k trong 3 s ln hn s cn li.

3. Hai trong 3 s c gi tr bng nhau.

4. Ba s c gi tr bng nhau.

Kt qu l:

R1. Thng bo ba gi tr nhp vo lp thnh tam gic thng.

R2. Thng bo ba gi tr nhp vo lp thnh tam gic cn.

R3. Thng bo ba gi tr nhp vo lp thnh tam gic u.

R4. Thng bo ba gi tr nhp vo khng lp thnh mt tam gic.

R5. Thng bo li nhp d liu.

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Hnh 3.1 th nguyn nhn kt qu:

Bc tip theo l to bng quyt nh mc vo gii hn. Chn kt qu R1 l

u tin. R1 c mt nu nt cc nt 12 v 3 = 1,0. Nt 12 = 1 khi 1 v 2 = 1,1.

p dng ln lt cho s c mt ca tng kt qu u vo, ta c bng quyt

nh nh sau:

Hnh 3.2 Bng quyt nh

1 2 3 4 5

1 1 1 1 1 0

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2 1 1 0

3 0 1

4 1

R1 1 0 0 0 0

R2 0 1 0 0 0

R3 0 0 1 0 0

R4 0 0 0 1 0

R5 0 0 0 0 1

Bc cui cng l chuyn i bng quyt nh thnh cc ca kim th. Cc ca

kim th thu c nh sau:

STT Cc iu kin Ca kim th Hnh ng

1 C 3 gi tr nhp vo u l s

nguyn dng, v tng ca 2 s

bt k trong 3 s lun ln hn s

th 3, v khng c cp 2 s bt

k no trong 3 s l = nhau.

2,3,4

2,4,3

3,2,4

3,4,2

4,2,3

4,3,2

R1

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nguyn dng, v tng cu 2 s

bt k trong 3 s lun ln hn s

th 3, v tn ti mt cp 2 s

trong 3 s l = nhau.

3,3,4

3,4,3

4,3,3

R2


nguyn dng, v c 3 s c gi

tr bng nhau.

3,3,3 R3


nguyn dng, v tn ti 2 s

trong 3 s c tng nh hn hoc

bng s cn li.

1,2,4

V 5 hon v ca

n

R4

5 Tn ti mt gi tr nhp vo

khng phi l s nguyn dng.

A,2,2

-1,1,1

1.1,1,1V 2 hon v ca

mi trng hp

R5

3.2.2 Phn lp tng ng

3.2.2.1 Xc nh cc lp tng ng

Cc gi tr nhp vo l s C 3 gi tr u l s (1) Tn ti 1 gi tr khng

phi l s (2)

Cc gi tr l nguyn C 3 gi tr u nguyn (3) Tn ti 1 gi tr khng

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nguyn (4)

Cc gi tr l dng C 3 gi tr u dng (5) Tn ti 1 gi tr


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1. 1, 1, 1

2. A, 1, 1 v 2 hon v.

3. 1.1, 1, 1 v 2 hon v.

4. 0, 1, 1 v 2 hon v.

5. -1, 1, 1 v 2 hon v.

6. -32768, 1, 1 v 2 hon v.

7. -32769, 1, 1 v 2 hon v.

8. 32767, 1, 1 v 2 hon v.

9. 32768, 1, 1 v 2 hon v.

10.1, 2, 3 v 5 hon v.

11.1, 2, 4 v 5 hon v.

3.2.3.2 Xt khng gian kt qu

Xt khng gian kt qu, thu c cc ca kim th nh sau:

Ba s u vo tha mn l 3 cnh ca mt tam gic u

12. 1, 1, 1

13. 32767, 32767, 32767

Ba s u vo tha mn l 3 cnh ca mt tam gic cn

14. 1, 1, 2 v 2 hon v.

15. 32767, 32767, 32766 v 2 hon v.

Ba s u vo tha mn l 3 cnh ca mt tam gic thng

16. 2, 3, 4 v 5 hon v.

17. 32767, 32766, 32765 v 5 hon v.

Ba s u vo khng tha mn l 3 cnh ca 1 tam gic

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Trong :

M1:Ba cnh A, B, C khng tha mn l 3 cnh ca 1 tam gic.

M2:Ba cnh A, B, C lp thnh 1 tam gic u.M3:Ba cnh A, B, C lp thnh 1 tam gic cn.

M4:Ba cnh A, B, C lp thnh 1 tam gic thng.

M5:Li nh dnh d liu. ngh bn xem v nhp li.

Cc ca kim th thu c:

1. -1, 1, 1 v cc hon v (abdl)

50

a+b>c anda+c>b and

b+c>a

l

j

S

k

S i

e

h

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2. 1, 1, 1 (abefhl)

3. 2, 2, 1 v cc hon v (abefijl)

4. 2, 3, 4 v cc hon v (abefikl)

5. 1, 2, 4 v cc hon v (abegl)6. A, 1, 1 v cc hon v (acl)

7. 1.1, 1, 1 v cc hon v (a,c,l)

3.2.4.2 Bao ph quyt nh

Cc ca kim th thu c:

1. -32768, -32768, -32768 v cc hon v (abdl)

2. 32767, 32767 , 32767 v cc hon v (abefhl)

3. 32767, 32767, 327676 v cc hon v (abefijl)

4. 32767, 32766, 32765 v cc hon v (abefikl)

5. 32767, 1, 2 v cc hon v (abegl)

6. A, 1, 1 v cc hon v (acl)

7. 1.1, 1, 1 v cc hon v (a,c,l)

3.2.4.3 Bao ph iu kin

Cc ca kim th thu c l:

1. -1, 1, 1 v cc hon v.

2. 2, 3, 4 v cc hon v.3. 1, 2 , 4 v cc hon v.

4. 2, 2, 1 v cc hon v.

5. 1, 1, 1 v cc hon v.

6. A, 1, 1 v cc hon v.

7. 1.1, 1, 1 v cc hon v.

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3.2.4.4 Bao ph quyt nh iu kin


1. -1, 1, 1 v cc hon v.

2. 2, 3, 4 v cc hon v.

3. 1, 2 , 4 v cc hon v.

4. 2, 2, 1 v cc hon v.

5. 1, 1, 1 v cc hon v.

6. A, 1, 1 v cc hon v.

7. 1.1, 1, 1 v cc hon v.

3.2.4.5 Bao ph a iu kin


1. -1, 1, 1 v cc hon v.

2. 2, 3, 4 v cc hon v.

3. 1, 2 , 4 v cc hon v.

4. 2, 2, 1 v cc hon v.

5. 1, 1, 1 v cc hon v.

6. A, 1, 1 v cc hon v.

7. 1.1, 1, 1 v cc hon v.

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KT LUN

Kim th phn mm, mt hng i khng cn mi m trn th gii, nhng lil mt hng i rt mi Vit Nam. N ha hn mt tng lai mi cho cc hc sinh,

sinh vin ngnh CNTT.

Qua tm hiu v xy dng ti ny, em thy mnh t c mt u im

cng nh vn cn mt s tn ti.

Nhng im t c:

Nm c tng quan v kim th phn mm: Cc khi nim c bn,

cc phng php kim th phn mm, v cc vn lin quan

Tm hiu v nm c cc phng php v chin lc thit k test

case trong kim th phn mm, v p dng c cc phng php tm

hiu xy dng cc test case cho 1 bi ton c th - Chng trnh

Tam gic. B sung v rn luyn thm k nng s dng phn mm Word v

Powerpoint.

Nng cao kh nng c hiu ti liu Ting Anh.

Nhng im cha t:

S p dng nhng kin thc tm hiu c mi ch dng li mt biton nh, m vn cha th p dng cho cc bi ton hay ng dng ln.

T nhng im t v cha t trn, em hi vng s nhn c s gp chn

thnh ca cc thy c v cc bn bn bo co c hon thin hn.

Sinh vin

Phm Th Trang

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TI LIU THAM KHO

1. The Art of Software Testing, Glenford J. Myers, Second Edition, John Wileyand Sons, Inc.

2. Software Engineering - A Practitioners Approach, Roger S.Pressman, Sixth

Edition, Ph.D, McGraw-Hill, Inc.

3. A Practitioner's Guide to Software Test Design, Lee Copeland, First Edition,

Artech House Publishers Boston, London.

4. Effective methods for Software Testing, William E. Perry, 3rd Edition, Wiley

Publishing, Indian.

5. Software Testing,Ron Patton, Second Edition, Sam Publishing.

6. http://www.vietnamesetestingboard.org/

7. http://en.wikipedia.org/wiki/Software_testing

8. Mt s trang web v kim th phn mm khc.

54
http://www.vietnamesetestingboard.org/http://en.wikipedia.org/wiki/Software_testinghttp://www.vietnamesetestingboard.org/http://en.wikipedia.org/wiki/Software_testing


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NHN XT CA GIO VIN HNG DN

Thi Nguyn, ngy thng 09 nm 2009

Gio vin hng dn

thiết kế testcase trong kiểm thử phần mềm

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