Copyright Jehad Al-Dallal Software Testing

Copyright Jehad Al-Dallal

Software Testing

Department of Computing Science

University of Alberta

CMPUT 402Software Engineering


Outlines Testing overview Testing object-oriented systems Testing object-oriented

frameworks Testing object-oriented framework

instantiations.


Testing Overview


Introduction Software testing

Verification activity Time consuming and costly. No correctness proof. Increase user confidence


Testing Phases Specification testing Design testing Implementation testing (software

testing) Dynamic Static


Test Suite

Testcase

…

Software test plan Document to explain testing approach

Testcase


Elements of a Test Case Reference number Description Preconditions Input Expected output


Test Case (TC) ExampleTC#: S-221TC Description: This test is to check the

response to an invalid input selection.TC Precondition: Go to screen

Flight_ManagementTC Input: Enter <F7>TC Expected Output: Error message:

“Invalid input, Enter “1” to “4” or ESC”


Implementation testing levels Unit testing Integration testing System testing Regression testing


Unit testing Module testing Testing approaches

Black-box White-box


Example: problem statement

Given two integers, find the larger.If larger is less than 1, return 1.


Example: Black-box testing

Given two integers, find the largest.If largest is less than 1, return 1.

TC description TC Inputs

n1>n2 n1=2, n1=1

n1<n2 n1=1, n2=2

n1=n2 n1=n2=2

….


White-box testing Statement coverage Graph based

Branch coverage Condition coverage Path coverage


Example: Statement Coverage1 int maxPositive(int n1, int n2) {2 if (n1<=1 && n2<=1) 3 n1=1;4 if (n1<=n2) 5 n1=n2;

6 return n1; }

TC Inputs: n1=n2=1


Example: Branch Coverage1 int maxPositive(int n1, int

n2) {2 if (n1<=1 && n2<=1) 3 n1=1;4 if (n1<=n2) 5 n1=n2;

6 return n1; }

1,2

3

4

5

6

TC#2 Inputs: n1=2, n2=0TC#1 Inputs: n1=n2=1


Example: Condition Coverage1 int maxPositive(int n1, int

n2) {2 if (n1<=1 && n2<=1) 3 n1=1;4 if (n1<=n2) 5 n1=n2;

6 return n1; } TC#1 Inputs: n1=n2=1TC#2 Inputs: n1=2, n2=0

1,2

3

4

5

6

TC#3 Inputs: n1=0, n2=2


Example: Path Coverage1 int maxPositive(int n1, int

n2) {2 if (n1<=1 && n2<=1) 3 n1=1;4 if (n1<=n2) 5 n1=n2;

6 return n1; } TC#1 Inputs: n1=n2=1TC#2 Inputs: n1=2, n2=0

TC#3 Inputs: n1=0, n2=2

1,2

3

4

5

6

TC#4 Inputs: n1=n2=0


Integration Testing Non-incremental (big-bang) Incremental

Top-down (stubs needed) Bottom-up (drivers needed) Sandwich


System Testing Performed in terms of Inputs and

outputs of the system. Performed on the targeted platform. Goals:

Reveal bugs that are represented only at system level.

Demonstrate that the system implements all required capabilities.

Answer the question: Can we ship it yet?


Regression Testing Ensuring that modifications have

not caused unintended effects. Retesting is required


Testing Object-Oriented Systems


Object-oriented testing Why it is different?

No sequential procedural executions. No functional decomposition. Unique problems

Encapsulation Inheritance Polymorphism


Object-oriented testing levels Method testing. Class testing. Cluster testing. System testing. Regression testing


Class testing Tests classes by sending messages

to methods one at a time. Requires drivers and stubs. May have to test more than one

method at a time to test the collaboration of methods.

Inherited method have to be tested.


Alpha-Omega Cycle Class Testing Alpha state: object declaration state. Omega state: object destruction state. Alpha-omega cycle testing: takes

objects from alpha to omega states by sending messages to every method at least once.

Method ordering (constructor, accessor, predicate, modifier, destructor)


ExampleClass person { person(String n, int a) { name=n; age=a; } constructor void setName(String n) { name=n; } modifier void setAge(int a) { age=a; } modifier String getName() { return name; } accessor int getAge() { return age; } accessor int isOld() { if age>50 return 1; return 0;} predicate String name; int age;

}


Example (Cont’d)Class driver { … void test() { person Tom= new Tom(“Tom”, 20); String name=Tom.getName(); int a=Tom.getAge(); if (Tom.isOld()) { … } setName(“old Tom!!”); setAge(60); … } …}


Cluster testing Cluster: collection of classes

cooperating with each other via messages.

Goal: test the interaction among the objects of the classes that forms the cluster.

Techniques: Message Quiescence Event Quiescence


Message Quiescence Method/Method path (MM-Path):

sequence of method executions linked by messages.

Starts with a method and ends with another method that does not issue a message.


meth1

meth3meth2

Class 1

meth1 meth3

meth2

meth2

meth1

Class 2

Class 3

Message

1

2

3

Event

MM-Path

MM-Paths


Event Quiescence Atomic System Function (ASF):

Input Event Output EventMM-Path


meth1

meth3meth2

Class 1

INPUT PORT EVENT

INPUT PORT EVENT

OUTPUT PORT EVENTA

A

meth1 meth3

meth2

meth2

meth1

BB

OUTPUT PORT EVENT

Class 2

Class 3

MM-Path

Message

1

2

3

Event


Example ATM pin entry

Customer enters card (event). Card is validated. Screen requesting pin entry is

displayed. Digits are touched and displayed. Pin is checked.


getKeyEvents

parseKeyEvent

showMessage

checkPin

memberCard

ValidateCard

Security

Screen CardSlot

NumKeypad

Customer inserts cardASF Starts here

Message is displayed

ASF ends here

Key pushers


Testing Object-Oriented Frameworks


Definitions OO-Framework

Reusable design and implementation of a system or subsystem [Beck+ 94]

Design + code + hooks Hooks

Places at which users can add their own components.


Importance Why do we have to care about

testing frameworks? Framework defects passes on to all

instantiations. Hard to discover framework defects at

the instantiation development stages. Little research has been carried out.


Framework testing Components (classes and small

clusters) black-box class associations

Hooks Compatibility and completeness Problem Solving


Testing OO-framework Problems Testing framework implementation

Developing testable model for the framework specifications.

Developing a test suite generator technique.

Testing framework hooks …


Testing OO-framework Problems (Cont’d) Testing framework hooks

Formalizing hook requirements. Developing testable model for hook

methods. Integrating hook method model with

framework specification model. Extending framework implementation test

suite generator technique. Developing an approach to test hook

compatibility and completeness


Testing Object-Oriented Framework Instantiations


Framework instantiation parts Framework used components. Interface components. Other instantiation components


Importance Why do we have to deal with

framework instantiations in a special way? Part of the code is tested. Part of the code is not needed. Part of the code is extended.


Testing framework instantiation problems Testing the used portion of the

framework code. Testing the extensibility of the

framework. Testing the framework interfaces. Testing other instantiation

components. Integration testing


Summary Testing importance OO-technology effects testing. OO-Framework technology effect

testing.


References G. Myers, The art of software testing, Wiley-

Interscience, 1979. B. Beizer, Software Testing Techniques, Van

Nostrand reinhold, 2nd edition, 1990. R. Binder, Testing object-oriented systems,

Addison Wesley, 1999. M. Hanna, Testing object-oriented systems for

QA professionals, PSQT/PSTT 2000 North Minneapolis, MN, conference tutorial H4, 2000.

M. Petchiny, Object-oriented testing, http://www.cs.queensu.ca/home/shepard/599.dir/petchiny/OOPRESENTATION.ppt

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