24 Testing Strategies

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CSC207 Lecture 24

Lecture 24

Testin Strate ies and Debu in

Testin Strate ies and Debu in



CSC207 Lecture 24

1. Unit Testing2. Inte ration Testin

3. Validation TestingPLAN

.

Each Task usesEach Task uses 1 test technique1 test technique



CSC207 Lecture 24

1. Unit Testing

Focuses on unit (e.g. object (class) & module)

Static – e.g. desk checking, compilation

-



CSC207 Lecture 24

Unit Testing forObjects:

ec r ver

Object (n/a) Object (n/a) Object Stub

Test harness (scaffolding)Test harness (scaffolding)



CSC207 Lecture 24

What forms the testharness?

-

Central

us omer

1:Order2:Check

: us omer

1:Order2:Check

souven rinfo

3:Check

antique

souven rinfo

3:Check

antique

Souvenirs Antiques Invoice Manager

: ssue nvo ce

:Souvenirs :Antiques :Invoice Manager

TransactionTransaction--basedbased



CSC207 Lecture 24

:CandidateAdministration

for examfor exam1:Register

3:Checkattendance

2:Verify

AU reqmts 3:Checkattendance

2:Verify

AU reqmts

:AU system:Attendance

:AU system:AttendanceUse caseUse case

on oron ordetermines testdetermines testharnessharness



CSC207 Lecture 24

Examples of Object

Drivers:

Driver 1

Object A B.OperationB Object B

OperationB

Driver 2

ect . pera on(attribC)

attribC

Object D

OperationD



CSC207 Lecture 24

Driver 3

fileE

Object F.

(rec-n )

OperationE OperationF



CSC207 Lecture 24

Ex m l f :

Object AA.OperationA

Object CC.O erationC

u

OperationA“table validated”

OperationC Returns record n

fileC

Stub 2

Object BB.OperationB

attributeB

OperationB Returns attributeB



CSC207 Lecture 24

Unit Testin forModules:

DRIVERCOMPILER

FLOW ANALYZER

WHITE BOX TESTING

BLACK BOX TESTING

STUB STUB

Test harness depends on module’s locationTest harness depends on module’s location



CSC207 Lecture 24

ADVANTAGES DISADVANTAGES

Narrows focus of test Requires test harness

Function tests lateEasier debugging

Parallel test efforts Requires scheduling



CSC207 Lecture 24

2. Integration Testing

Non-incremental



CSC207 Lecture 24

-(Big-Bang Approach)

Components are first unit tested

Assembly of every components at the same

time Suitable for small to moderate sized systems



CSC207 Lecture 24

Disadvantages:

Excessive use of test harness D in i h r r

Concentrated use of limited resources



CSC207 Lecture 24

ncremen a pproac(OO Systems)

••StimulusStimulus OrderOrder (use(use--based)based)

••RegressionRegression teststests maymay bebe neededneeded

••

••DetermineDetermine “bottlenecks”“bottlenecks” ifif anyany

••UseUse testtest scheduleschedule toto synchronisesynchronise



CSC207 Lecture 24

:CandidateAdministration

1:Register

3:Checkattendance

2:VerifyAU reqmts2:VerifyAU reqmts

3:Checkattendance


Monitor


Monitor



CSC207 Lecture 24

Exam le 2:Exam le 2:

:e-RetailCentral

Customer:Customer

2:Checksouvenir

1:Order1:Order

2:Checksouvenir

4:Issue invoice

: ecantique

info

: ecantique

info4:Issue invoice

Invoice ManagerSouvenirsRetail

AntiquesRetail

:SouvenirsRetail

:AntiquesRetail

:Invoice Manager



CSC207 Lecture 24

Example 3:Example 3: :HotelMS

bottleneckbottleneck

:Guests :Booking :Rooms3:update

2:check status

:Walk-ins :Tourists1:enquire



CSC207 Lecture 24

(FO Systems)

Guided by Structure Chart

Top-Down (Depth or Breadth)

Bottom-Up (Depth, Breadth orCluster)

Sandwich Approach



CSC207 Lecture 24

op- own ep - rs

AA

B C D

TOP-

DOWNB C D



CSC207 Lecture 24

opop-- own reaown rea -- rsrs

AA

B C D

TOP-

DOWNB C D



CSC207 Lecture 24

-- --

AA

B C D

BOTTOM-UP

B C D



CSC207 Lecture 24

-- --

AA

B C D

BOTTOM-UP

B C D



CSC207 Lecture 24

--

AA

B C D

BOTTOM-UP

B C D



CSC207 Lecture 24

--

AA

B C D

SANDWICH

B C D



CSC207 Lecture 24

--

AA

B C D

SANDWICH

B C D



CSC207 Lecture 24

3. Validation Testing

Black box testing

– c ec s con ormance o

Acceptance testsalpha testing: 1 client (bespoke system)

beta testing: many clients



CSC207 Lecture 24

4. System Testing

After installation andcomm ss on ng

Focus on daily operations Black box testing

e. . stress testin sensitivit testin



CSC207 Lecture 24

e ugg ng

1. Brute force.

3. Cause Elimination



CSC207 Lecture 24

1. Brute force

Memory Dumps

Least efficient (used when all else fails)



CSC207 Lecture 24

2. Backtracking

Begin at error discovery point

Suitable for small to moderate-sized



CSC207 Lecture 24

3. Cause Elimination

By induction or deduction“ ”

Organise test cases to isolate potential

Suitable for larger programs or sub-



CSC207 Lecture 24

debuggedrea po n s,rea po n s,

steppingstepping

Program

Execution

User

symbolinteractionmanager

RecordsRecords

TracePackage

Symbol ValueRecorder

program owprogram ow

RecordsRecords

data contentsdata contents



CSC207 Lecture 24

T r – r niz i n f k

Tasks: unit, integration, validation, system

Integration for OO systems: stimulus order

order

Validation & S stem Testin

•• Next lectureNext lecture – – Software MaintenanceSoftware Maintenance

24 Testing Strategies

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