OOAD-Unit-5-Testing approaches and types of testing Strategies

CS8592 - OBJECT ORIENTED ANALYSIS
AND DESIGN
UNIT V TESTING
Object Oriented Methodologies – Software Quality Assurance – Impact of
object orientation on Testing – Develop Test Cases and Test Plans.
Introduction.
Object oriented systems development is a way to develop software by building
self – contained modules or objects that can be easily replaced, modified and reused.
In an object–oriented environment, software is a collection of discrete objects that
encapsulate their data as well as the functionality of model real–world events
“objects” and emphasizes its cooperative philosophy by allocating tasks among the
objects of the applications. A class is an object oriented system carefully delineates
between its interface (specifications of what the class can do) and the implementation
of that interface (how the class does what it does).
A method is an implementation of an object's behavior. A model is an abstract
of a system constructed to understand the system prior to building or modifying it.
Methodology is going to be a set of methods, models and rules for developing systems
based on any set of standards. The process is defined as any operation being
performed.
5.1OBJECT ORIENTED METHODOLOGIES
Object oriented methodologies are set of methods, models, and rules for
developing systems. Modeling can be done during any phase of the software life cycle
.A model is a an abstraction of a phenomenon for the purpose of understanding the
methodologies .Modeling provides means of communicating ideas which is easy to
understand the system complexity .
Object-Oriented Methodologies are widely classified into
three
1.The Rumbaugh et al. OMT (Object modeling technique)
2.The Booch methodology
3.Jacobson's methodologies
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A methodology is explained as the science of methods. A method is a set of
procedures in which a specific goal is approached step by step. Too min any
Methodologies have been reviewed earlier stages.
 In 1986, Booch came up with the object-oriented design concept, the Booch
method.
 In 1987,Sally Shlaer and Steve Mellor came up with the concept of the
recursive design approach.
 In 1989, Beck and Cunningham came up with class-responsibility collaboration
(CRC) cards.
 In 1990,Wirfs-Brock, Wilkerson, and Wiener came up with responsibility
driven design.
 In 1991, Peter Coad and Ed Yourdon developed the Coad lightweight and
prototype-oriented approach. In the same year Jim Rumbaugh led a team at the
research labs of General Electric to develop the object modeling technique
(OMT).
 In 1994,Ivar Jacobson introduced the concept of the use case.
These methodologies and many other forms of notational language provided
system designers and architects many choices but created a much split, competitive
and confusing environment. Also same basic concepts appeared in very different
notations, which caused confusion among users .Hence, a new evolvement of the
object oriented technologies which is called as second generation object-oriented
methods.
Advantages /Charecteristics

The Rumbaugh et al. method is well-suited for describing the object model or static
structure of the system.
The Jacobson et.al method is good for producing user-driven analysis models
The Booch method detailed object-oriented design models
Rumbaugh et. al.’s Object Modeling Technique (OMT)
OMT describes a method for the analysis, design, and implementation of a system
using an object-oriented technique.
Class, attributes, methods, inheritance, and association also can be expressed easily
The dynamic behavior of objects within a system can be described using OMT
Dynamic model
 Process description and consumer-producer relationships can expressed using
OMT’s Functional model
OMT consists of four phases, which can be performed iteratively:
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1. Analysis. The results are objects and dynamic and functional models.
2. System design. The result is a structure of the basic architecture of the system.
3. Object design. This phase produces a design document, consisting of detailed
objects and dynamic and functional models.
4. Implementation. This activity produces reusable, extendible, and robust code.
OMT separates modeling into three different parts:
1. An object model, presented by the object model and the data dictionary.
2. A dynamic model, presented by the state diagrams and event flow diagrams.
3. A functional model, presented by data flow and constraints.
OMT Object Model
The object model describes the structure of objects in a system:
Their identity , relationships to other objects, attributes, and operations
The object model is represented graphically with an object diagram
The object diagram contains classes interconnected by association lines
Example of an object model
 The above example provides OMT object model of a bank system. The boxes
represent classes and the filled triangle represents specialization.
 Association between Account and Transaction is one-to-many. Since one
account can have many transactions, the filled circle represents many (zero or
more).
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 The relationship between Client and Account classes is one-to-one. A client
can have only one account and account can belong to only one person (in this
model joint accounts are not considered )
OMT Dynamic Model

OMT dynamic model depict states, transitions, events, and actions

OMT state transition diagram is a network of states and events
Each state receives one or more events, at which time it makes the transition to the
next state.
Example of a state transition for ATM Transaction
Here the round boxes represent states and the arrows represent transitions
OMT Functional Model
The OMT DFD shows the flow of data between different process in a business
DFD use four primary symbols:
Process is any function being performed ; For Ex, verify password or PIN in the
ATM system
Data flow shows the direction of data element movement: foe Ex. PIN code
Data store is a location where data are stored: for ex. Account is a data store in the
ATM example
External entity is a source or destination of a data element; fro ex. The ATM card
Reader
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On the whole , the Rumbaugh et al .OMT methodology provides one of the strongest
tool sets for the analysis and design of object-oriented systems .
Example of OMT DFD of an ATM
system
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The above example is OMT DFD of the ATM system .The data flow lines
include arrows to show the direction of data element movement .The circle represents
processes. The boxes represents external entities .A data store reveals the storage of
data.
The Booch Methodology

It is a widely used object oriented method that helps us to design the system
using object paradigm.
The Booch methodology covers the analysis and design phases of systems
development.
Booch sometimes is criticized for his large set of symbols.
You start with class and object diagram in the analysis phase and refine these
diagrams in various steps.
The Booch method consists of the following diagrams:
– Class diagrams
– Object diagrams
– State transition diagrams
– Module diagrams
– Process diagrams
– Interaction diagrams
Object Modeling using Booch Notation
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Example :Alarm class state transition diagram with Booch notation.The arrows
represents specialization
The Booch methodology prescribes
– A macro development process serve as a controlling framework for the micro
process and can take weeks or even months. The primary concern of the macro
process is technical management of the system
– A micro development process.
The macro development process consists of the following steps:
1. Conceptualization :
 you establish the core requirements of the system
 You establish a set of goals and develop a prototype to prove the concept
2. Analysis and development of the model.
Use the class diagram to describe the roles and responsibilities objects are to carry out
in performing the desired behavior of the system .Also use the Object diagram to
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describe the desired behavior of the system in terms of scenarios or use the interaction
diagram.
3. Design or create the system architecture.
In this phase, You use the class diagram to decide what class exist and how they relate
to each other .Object diagram to used to regulate how objects collaborate. Then use
module diagram to map out where each class and object should be declared. Process
diagram – determine to which processor to allocate a process.
4. Evolution or implementation. – refine the system through many iterations
5. Maintenance. - make localized changes the the system to add new requirements
and eliminate bugs.
Micro Development Process
Each macro development process has its own micro development process
The micro process is a description of the day to- day activities by a single or small
group of
s/w developers
The micro development process consists of the following steps:
1. Identify classes and objects.
2. Identify class and object semantics.
3. Identify class and object relationships.
4. Identify class and object interfaces and implementation.
The Jacobson et al. Methodologies
The Jacobson et al. methodologies (e.g., OOBE, OOSE, and Objectory) cover the
entire life cycle and stress traceability between the different phases both forward and
backward. This traceability enables reuse of analysis and design work, possibly much
bigger factors in the reduction of development time than reuse of code.
Use Cases
Use cases are scenarios for understanding system requirements.
A use case is an interaction between users and a system.
The use-case model captures the goal of the user and the responsibility of the system
to its users.
The use case description must contain:
– How and when the use case begins and ends.
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– The interaction between the use case and its actors, including when the interaction
occurs and what is exchanged. How and when the use case will store data in the
system.
– Exceptions to the flow of events.
 Every single use case should describe one main flow events
 An exceptional or additional flow of events could be added
 The exceptional use case extends another use case to include the additional one
 The use-case model employs extends and uses relationships
 The extends relationship is used when you have one use case that is similar to
another use case
The uses relationships reuse common behavior in different use cases
Use cases could be viewed as a concrete or abstract
Abstract use case is not complete and has no actors that initiate it but is used by
another use case.
Abstract Usecase
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ATM Transaction use cases.
Object-Oriented Software Engineering: Objectory
 Object-oriented software engineering (OOSE), also called Objectory, is a
method of object oriented development with the specific aim to fit the
development of large, real-time systems. The development process, called use-
case driven development, stresses that use cases are involved in several phases
of the development.
 The system development method based on OOSE is a disciplined process for
the industrialized development of software, based on a use-case driven design.
It is an approach to object-oriented analysis and design that centers on
understanding the ways in which a system actually is used.
 By organizing the analysis and design models around sequences of user
interaction and actual usage scenarios, the method produces systems that are
both more usable and more robust, adapting more easily to changing usage
 The maintenance of each model is specified in its associated process. A process
is created when the first development project starts and is terminated when the
developed system is taken out of service
Objectory is built around several different models:
– Use case model.
– defines the outside ( actors) and inside(use case) of the system behavior
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– Domain object model. The object of the “real” world are mapped into
the domain object model
– Analysis object model.
– how the source code (implementation) should be carried out and written
– Implementation model.
– represents the implementation of the system
– Test model.
- constitute the test plan, specifications, and reports
Object-Oriented Business Engineering (OOBE)
Object-oriented business engineering (OOBE) is object modeling at the enterprise
level. Use cases again are the central vehicle for modeling, providing traceability
throughout the software engineering processes.
OOBE consists of : object modeling at enterprises level
– Analysis phase
 The analysis phase defines the system to be built in terms of the problem-
domain object model, the requirements model and the analysis model .This
reduces complexity and promotes maintainability over the life of the system
,since the description of the system will be independent of hardware and
software requirements .
 The analysis process is iterative but the requirements and the analysis models
should be stable before moving on to subsequent models. Jacobson et al.
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suggest that prototyping with a tool might be useful during this phase to help
specify user interfaces.
– Design& Implementation phases
 The implementation environment must be identified for the design model .
This include factors such as DBMS, distribution of process ,constraints due to
the programming language, available component libraries and incorporation
user interface tools
 It may be possible to identify implementation environment concurrently with
analysis. The analysis objects that fit the current implementation environment.
– Testing phase.
Finally Jacobson describes several testing levels and techniques such as unit
testing, integration testing and system testing.
Patterns
A design pattern is defined as that it identifies the key aspects of a common
design sturture that make it useful for creating a reusable object-orinted design . It also
identifies the participating classes and instances their roles and collaborations and the
distribution of responsibilities.[Gamma,Helson,Johnson definition ]
A pattern involves a general description of solution to a recurring problem
bundle with various goals and constraints. But a pattern does more than just identify a
solution; it also explains why the solution is needed.
A pattern is useful information that captures the essential structure and insight of a
successful family of proven solutions to a recurring problem that arises within a
certain context and system of forces.
Its help software developers resolve commonly encountered, difficult problems and
a vocabulary for communicating insight and experience about these problems and
their solutions.
The main idea behind using patterns is to provide documentation to help categorize
and communicate about solutions to recurring problems.
The pattern has a name to facilitate discussion and the information it represents.
A good pattern will do the following:
It solves a problem.
Patterns capture solutions, not just abstract principles or strategies.
It is a proven concept.
Patterns capture solutions with a track record, not theories or speculation.
The solution is not obvious.
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The best patterns generate a solution to a problem indirectly—a necessary approach
for the most difficult problems of design.
It describes a relationship.
Patterns do not just describe modules, but describe deeper system structures and
mechanisms.
Generative and Non-Generative Patterns
 Generative patterns are the patterns that not only describe a recurring problem
but also tell us how to generate something and can be observed in the resulting
system architectures.
 Non-generative patterns are static and passive .They describe recurring
phenomena without necessarily saying how to reproduce them.
Patterns Template
Every pattern must be expressed in form of a template which establishes a
relationship between a context , a system of forces which raises in that context and a
configuration which allows these forces to resolve themselves in that context. The
following components should be present in a pattern template
 Name –A meaningful name .This allows us to use a singlew word or short
phrase to refer a pattern and the knowledge and the structure it
describes.Sometimes a pattern may have more than one commonly used or
recognizable name in the literature .In this case nick names can be used .
 Problem-A statement of a problem that describes its intent: the goals and
objectives it wants to reach within the given context and forces .
 Context-The preconditions under which the problem and its solution seem to
recur and for which solution is desirable. This tells us about the pattern
applicability.
 Forces-A description of the relevant forces and constraints and how they
interact or conflict with one another and with goals to that wish to achieve.
Forces reveal the intricacies of the problem and define the kinds of trade-offs
that must be considered in the presences of the tension or dissonance they
create. A good pattern description should fully encapsulate all the forces that
have an impact on it.
 Solution
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 Examples
 Resulting context
 Rationale
 Related Patterns
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 Known uses-The known occurrences of the pattern and its application within
existing systems .This helps validate a pattern by verifying that it indeed is a
proven solution to a recurring problem .
AntiPatterns

A pattern represents a “best practice” whereas an antipattern represents “worst
practice” or a
“lesson leaned”

Antipattern come in two verities:
Those describe a bad solution to a problem that resulted in a bad situation
Those describing how to get out of a bad situation and how to proceed from there to
a good solution

The pattern has a significant human component.
- All software serves human comfort or quality of life.
-The best patterns explicitly appeal to aesthetics and utility.
Capturing Patterns
 Patterns should provide not only facts but also tell us a story that captures the
experience they are trying to convey.
 A pattern should help its users comprehend existing systems, customize
systems to fit user needs, and construct new systems.
 The process of looking for patterns to document is called pattern mining.
Guidelines for capturing patterns:
– Focus on practicability.-Patterns should describe proven solutuions to recurring
problems rather than the latest scientific results .
– Aggressive disregard of originality.-Pattern writers do not need to be the original
inventor or discoverer of the solutions that they document.
– Non-anonymous review.-Paper submissions are shepherded rather than reviewed. It
contacts the pattern authors and discusses with him or her how the patterns might be
clarified or improved on
– Writers' workshops instead of presentations.-Open forums are used here to improve
the patterns which are lacking
– Careful editing
.-Incorporating all the review comments and insights given by the writers workshops.
Frameworks

A framework is a way of presenting a generic solution to a problem that can be
applied to all
levels in a development.
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
A single framework typically encompasses several design patterns and can be viewed
as the
implementation of a system of design patterns.
A definition of object oriented software framework is given by Gamma et al.
Differences between Design Patterns and Frameworks
Design patterns are more abstract than frameworks.
Design patterns are smaller architectural elements than frameworks.
Design patterns are less specialized than frameworks.
The Unified Approach
The idea behind the UA is not to introduce yet another methodology.
The main motivation here is to combine the best practices, processes, methodologies,
and guidelines along with UML notations and diagrams.
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The unified approach to software development revolves around (but is not limited to)
the following processes and components.
The processes are:
– Use-case driven development.
– Object-oriented analysis.
– Object-oriented design.
– Incremental development and prototyping.
– Continuous testing.
UA Methods and Technology
The methods and technology employed includes:
– Unified modeling language (UML) used for modeling.
– Layered approach.
– Repository for object-oriented system development patterns and frameworks.
– Promoting Component-based development.
UA Object-Oriented Analysis:
Use-Case Driven
The use-case model captures the user requirements.
The objects found during analysis lead us to model the classes.
The interaction between objects provide a map for the design phase to model the
relationships and designing classes.
OOA Process consists of the following steps :
1. Identify the Actors
2. Develop the simple business process model using UML activity diagram
3. Develop the Use Case
4. Develop interaction diagrams
5. Identify classes
UA Object-Oriented Design:
Booch provides the most comprehensive object-oriented design method.
However, Booch methods can be somewhat imposing to learn and especially tricky
to figure out where to start.
UA realizes this by combining Jacobson et al.'s analysis with Booch's design concept
to create a comprehensive design process.
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OOD Process consists of:
Design classes , their attributes, methods, associations, structures and protocols,
apply design axioms
Design the Access Layer
Design and prototype User Interface
User satisfaction and usability Test based on the usage / Use cases
Iterative Development and Continuous Testing

The UA encourages the integration of testing plans from day 1 of the project.
Usage scenarios or Use Cases can become test scenarios; therefore, use cases will
drive the usability testing.
You must iterate and reiterate until, you are satisfied with the system.
Modeling Based on the Unified Modeling Language
The UA uses the unified modeling language (UML) to describe and model the
analysis and design phases of system development.
The UA Proposed Repository
The requirement, analysis, design, and implementation documents should be stored
in the repository, so reports can be run on them for traceability.
This allows us to produce designs that are traceable across requirements, analysis,
design, implementation, and testing.
Two-Layer Architecture
In a two-layer system, user interface screens are tied directly to the data through
routines that sit directly behind the screens.
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This approach results in objects that are very specialized and cannot be reused easily
in other projects.
Three-Layer Architecture
Your objects are completely independent of how:
– they are represented to the user (through an interface) or
– how they are physically stored.
User Interface layer
This layer consists of objects with which the user interacts as well as the objects
needed to manage or control the interface. It is also called as a view layer. The UI
interface layer objects are indentified during OOD phase .
This layer is typically responsible for two major aspects of the applications:
 Responding to user interaction-Here the user interface layer objects must be
designed to translate actions by the user , such as clicking on a button or selecting
from a menu ,into an appropriate response .
That response may be to open or close another interface or to send a message down
into the business layer to start some business process.
Displaying business objects.-The display of the objects is shown by using list boxes
and graphs
Business Layer
1.The responsibilities of the business layer are very straightforward:
2.model the objects of the business and how they interact to accomplish the business
processes.
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Business Layer: Real Objects
These objects should not be responsible for:
Access Layer
The access layer contains objects that know how to communicate with the place
where the data actually resides,

Whether it be a relational database, mainframe, Internet, or file.
The access layer has two major responsibilities:
Translate request-This layer must be able to translate any data-related requests from
the business layer into the appropriate protocol for data access.(For eg . if a customer
number 5333 is to be retrieved from the Database , an SQL statement is created by the
access layer and execute it )
Translate result –It translates the data retrieved back into the appropriate business
objects and passes those objects back up into the business layer
Architecture for Access layer ,Business layer and view layer
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5.2 SOFTWARE QUALITY ASSURANCE
The major key areas of SQA are
 Bugs and Debugging
 Testing strategies.
 The impact of an object orientation on testing.
 How to develop test cases.
 How to develop test plans.
Two issues in software qualityare:
 Validation or user satisfaction
 Verification or quality assurance.
Elimination of the syntactical bug is the process of debugging. Detection and
elimination of the logical bug is the process of testing.
Error Types:

Language errors or syntax errors

Run-time errors

Logic errors
Identifying Bugs and Debugging

The first step in debugging is recognizing that a bug exists.

Sometimes it's obvious; the first time you run the application, it shows itself.

Other bugs might not surface until a method receives a certain value, or until you
take a closer look at the output
However, these steps might help:
 Selecting appropriate testing strategies
 Developing test cases and sound test plan.
Debugging Tools

Debugging tools are a way of looking inside the program to help us determine what
happens and why.

It basically gives us a snapshot of the current state of the program.
Testing Strategies
There are four types of testing strategies, These are:
 Black Box Testing
 White Box Testing
 Top-down Testing
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 Bottom-up Testing
Black Box Testing

In a black box, the test item is treated as "black" whose logic is unknown.

All that's known is what goes in and what comes out, the input and output

Black box test works very nicely in testing objects in an Object-Oriented
environment.
White Box Testing
White box testing assumes that specific logic is important, and must be tested
to guarantee system’s proper functioning. This testing looks for bugs that have a low
probability of execution that has been overlooked in previous investigations. The main
use of this testing is error-based testing , when all level based objects are tested
carefully .
One form of white box testing is called path testing

It makes certain that each path in a program is executed at least once during testing.
Two types of path testing are:
 Statement testing coverage- The main idea of the statement testing coverage is
test every statement in the objects method executing it at least once.
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 Branch testing coverage –The main idea here is to perform enough tests to
ensure that every branch alternative has been executed at least once under some
test. It is feasible to fully test any program of considerable size.
Top-down Testing
It assumes that the main logic of the application needs more testing than supporting
logic.
Bottom-up Approach

It takes an opposite approach.

It assumes that individual programs and modules are fully developed as standalone
processes.

These modules are tested individually, and then combined for integration testing.
System Usability & Measuring User Satisfaction

Verification
- "Am I building the product right?"
Validation
- "Am I building the right product?"
Two main issues in software quality are
Validation or user satisfaction and
verification or quality assurance.

The process of designing view layer classes consists of the following steps:
1. In the macro-level user interface (UI) design process, identify view layer objects.
2. In the micro-level UI, apply design rules and GUI guidelines.
3. Test usability and user satisfaction.
4. Refine and iterate the design.
Usability and User Satisfaction Testing
Two issues will be discussed:
1. Usability Testing and how to develop a plan for usability testing.
2.User Satisfaction Test and guidelines for developing a plan for user satisfaction
testing.

The International Organization for Standardization (ISO) defines usability as the
effectiveness ,efficiency, and satisfaction with which a specified set of users can
achieve a specified set of tasks in particular environments.
Defining tasks. What are the tasks?
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Defining users. Who are the users?
A means for measuring effectiveness, efficiency, and satisfaction
The phrase two sides of the same coin is helpful for describing the relationship
between the
Usability and functionality of a system.
Bottom – Up Testing
It supports testing user interface and system integration. In the bottom-up strategy,
each module at lower levels is tested with higher modules until all modules are tested.
It takes help of Drivers for testing
Advantages:
 Fault localization is easier.
 No time is wasted waiting for all modules to be developed unlike Big-bang
approach
Disadvantages:
 Critical modules (at the top level of software architecture) which control the
flow of application are tested last and may be prone to defects.
 An early prototype is not possible
Top-down Testing:
In Top to down approach, testing takes place from top to down following the control
flow of the software system. Takes help of stubs for testing. It starts with the details of
the system and proceeds to higher levels by a progressive aggregation of details until
they fit requirements of system.
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Advantages:
 Fault Localization is easier.
 Possibility to obtain an early prototype.
 Critical Modules are tested on priority; major design flaws could be found and
fixed first.
Disadvantages:
 Needs many Stubs.
 Modules at a lower level are tested inadequately.
5.3 IMPACT OF OBJECT ORIENTATION ON TESTING
Errors.
٥ Less Plausible ( not worth testing for )
٥ More Plausible ( worth testing for now)
٥ New types of errors may appear
Impact of Inheritance on Testing.
 Does not reduce the volume of test cases
 Rather, number of interactions to be verified goes up at each level of the
hierarchy
 Testing approach is essentially the same for OO oriented and Non-Object
oriented environment.
 However, can reuse superclass/base class test cases
 Since OO methods are generally smaller, these are easier to test . But there are
more opportunities for integration faults.
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Reusability of tests.
Reusable Test Cases and Test Steps is a tool to improve re-usability and
maintainability of Test Management by reducing redundancy between Test Cases in
projects. Often the Test scenarios require that some Test Cases and Test Steps contain
repeated or similar actions performed during a Testing cycle.
The models used for analysis and design should be used for testing at the same
time. The class diagram describes relationship between objects .which is a useful
information form testing .Also it shows the inheritance structure which is important
information for error-based testing.
Error based testing
Error based testing techniques search a given class’s method for particular clues of
interests, and then describe how these clues should be tested.
Usability testing
Measures the ease of use as well as the degree of comfort and satisfaction users have
with the software.

Usability testing must begin with defining the target audience and test goals.

Run a pilot test to work out the bugs of the tasks to be tested.

Make certain the task scenarios, prototype, and test equipment work smoothly.
Guidelines for Developing Usability Testing
―Focus groups" are helpful for generating initial ideas or trying out new ideas.
It requires a moderator who directs the discussion about aspects of a task or design

Apply usability testing early and often.

Include all of software‘s components in the test.

The testing doesn‘t need to be very expensive, a tape recorder, stopwatch, notepad
and an office can produce excellent results.

Tests need not involve many subjects.

More typically, quick, iterative tests with a small, well-targeted sample of 6 to 10
participants can identify 80– 90 percent of most design problems.

Focus on tasks, not features.

Remember that your customers will use features within the context of particular
tasks.

Make participants feel comfortable by explaining the testing process.

Emphasize that you are testing the software, not the participants.
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
If they become confused or frustrated, it is not a reflection on them.

Do not interrupt participants during a test.

If they need help, begin with general hints before moving to specific advice.

Keep in mind that less intervention usually yields better results.

Record the test results using a portable tape recorder, or better, a video camera.

You may also want to follow up the session with the user satisfaction test.

The test is inexpensive, easy to use and it is educational to those who administrate it
and those who fill it out. Even if the results may never be summarized, or filled out,
the process of creating the test itself will provide us with useful information.
5.4 TEST CASES
A test case is a set of What – if questions. To test a system you must construct some
best input cases, that describe how the output will look. Next, perform the tests and
compare the
outcome with the expected output.
Myer’s (objective of testing )
Testing is a process of executing a program with the intent of finding errors.
Good test case.That has a high probability of finding an as – yet – undiscovered error.
Successful test case That detects an as – yet – undiscovered error.
Guidelines for Developing quality assurance test cases.
Freedman and Thomas have developed guidelines that have been adopted for the UA:
 Describe which feature or service your test attempts to cover.
 If the test case is based on a use case, it is good idea to refer to the use-case
name.
 Specify what you are testing and which particular feature.
 test the normal use of the object methods.
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 test the abnormal but reasonable use of the objects methods.
 test the boundary conditions.
 Test objects interactions and the messages sent among them.
 Attempting to reach agreement on answers generally will raise other what-if
questions.
 The internal quality of the software, such as its reusability and extensibility,
should be assessed as well.
5.5TEST PLAN
‫٭‬ A Test plan is developed to detect and identify potential problems before delivering
the
software to its users.
‫٭‬ A test plan offers a road map.
‫٭‬ A dreaded and frequently overlooked activity in software development.
Steps
 Objectives of the test.- create the objectives and describes how to achieve them
 Development of a test case- develop test case, both input and expected output.
 Test analysis.- This step involves the examination of the test output and the
documentations of the test results
Regression Testing.- All passed tests should be repeated with the revised program,
called "Regression". This can discover errors introduced during the debugging
process. When sufficient testing is believed to have been conducted, this fact should
be reported, and testing to this specific product is complete
Beta Testing.
Beta Testing can be defined as the second stage of testing any product before
release where a sample of the released product with minimum features and
characteristics is being given to the intended audience for trying out or temporarily
using the product.
Unlike an alpha test, the beta test is being carried out by real users in the real
environment. This allows the targeted customers to dive into the product's design,
working, interface, functionality, etc.
Alpha Testing.
Alpha Testing can be defined as a form of acceptance testing which is carried
out for identifying various types of issues or bugs before publishing the build or
executable of software public or market. This test type focuses on the real users
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through black box and white box testing techniques. The focus remains on the task
which a general user might want or experience.
Alpha testing any product is done when product development is on the verge of
completion. Slight changes in design can be made after conducting the alpha test. This
testing methodology is performed in lab surroundings by the developers.
Here developers see things in the software from users point and try to detect the
problems. These testers are internal company or organization's employees or may be a
part of the testing team. Alpha testing is done early at the end of software
development before beta testing.
Guidelines (for preparing test plan)
 Specify Requirements generated by user.
 Specify Schedule and resources.
 Determine the testing strategy.
 Configuration Control System.
 Keep the plan up to date.
 At the end of each milestone, fill routine updates.
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MYER’S DEBUGGING PRINCIPLES
Bug locating principles.
 Think
 If you reach an impasse, sleep on it.
 If the impasse remains, describe the problem to someone else. Use debugging
tools.
 Experimentation should be done as a last resort.
Debugging principles.
 Where there is one bug , there is likely to be another.
 Fix the error, not just the symptom.
 The probability of solution being correct drops down as the size increases.
 Beware of error correction, it may create new errors
Case study :
Develping Test cases for vianet ATM bank system
Test cases are derived from the following use case scenarios
1. Bank Transaction
2. Checking transaction history
3. Savings/current account
4. Deposit/Withdarw
5. valid/invalid PIN
Example of vianet ATM system for user satisfaction test
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