Software quality assurance

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Software Quality Assurance

Prof. Erwin M. Globio, MSIT

Senior IT Lecturer

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Software Quality

•Quality software is reasonably bug-free

•delivered on time

•within budget

•meets requirements and/or expectations

•maintainable.

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Software Quality

• Conformance to explicitly stated functional

and performance requirements

• explicitly documented development

standards

• implicit characteristics that are expected of

all professionally developed software.

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Software Quality

Emphasis:

1. Software requirements are the foundation from which quality is measured.

2. Specified standards define a set of development criteria that guide the manner in which software is engineered.

3. There is a set of implicit requirements that often goes unmentioned.

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Categories of software quality factors

1. Factors that can be directly measured (e.g. errors)

2. Factors that can be measured indirectly (e.g. usability)

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McCall Software Quality Factors

Product Operations

Product Revisions

Product Transition

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Product Operations

Correctness (Does it do what I want?)

Reliability (Does it do it accurately all of the

item?)

Efficiency (Will it run on my hardware as well

as it can?)

Integrity (Is it secure?)

Usability (Can I run it?)

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Product Revisions

Maintainability (Can I fix it?)

Flexibility (Can I change it?)

Testability (Can I test it?)

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Product Transition

Portability (Will I be able to use if on

another machine?)

Reusability (Will I be able to reuse some

of the software?)

Interoperability (Will I be able to interface

it with another system?)

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Metrics that affect the quality factor

• Auditability • Accuracy• Communication

commonality• Completeness• Concisenes.• Data commonality• Consistency• Error Tolerance.• Execution efficiency.• Expandability.• Generality

• Hardware Independence

• Instrumentation.• Modularity.• Operatibility.• Security• Self-documentation.• Simplicity.• Software system

independence.• Traceability.• Training.

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Software Quality Assurance

Involves the entire software development PROCESS - monitoring and improving the process, making sure that any agreed-upon standards and procedures are followed, and ensuring that problems are found and dealt with.

It is oriented to 'prevention'.

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SQA encompasses:

• analysis, design, coding and testing methods

and tools

• formal technical reviews that are applied during

each software engineering step

• a multitiered testing strategy

• control of software documentation and the

changes made to it

• a procedure to assure compliance with software

development standards

• measurement and reporting mechanisms.

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Reasons Why Software Have Bugs

miscommunication or no communication

software complexity

programming errors

changing requirements

time pressures

egos

poorly documented code

software development tools

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SQA Approaches

1. Verification and Validation

2. Walkthrough

3. Inspection

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Common Problems in Software Development Process

poor requirements

unrealistic schedules

inadequate testing

featuritis

miscommunication

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Common Solutions to Software Development Process Problems

solid requirements

realistic schedules

adequate testing stick to initial

requirements as much as possible

communication

tools

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SQA Activities

Application of technical methods.

Conduct of formal technical reviews..

Testing of software..

Enforcement of Standards..

Control of change.

Measurement.

Recordkeeping and reporting.

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Good Code

a code that works, is bug free, and is

readable and maintainable

It should be kept in mind that excessive

use of standards and rules can stifle

productivity and creativity

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Good Design

• clear

• understandable

• easily modifiable and maintainable

• is robust with sufficient error-handling and

status logging capability

• works correctly when implemented

Good internal design is indicated by software

code whose overall structure is:

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Good Design

Good functional design is indicated by an

application whose functionality can be traced

back to customer and end-user requirements.

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Good User-Interface

• the program should act in a way that least surprises the user

• it should always be evident to the user what can be done next and how to exit

• the program shouldn't let the users do something stupid without warning them

Useful Websites

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http://erwinglobio.wix.com/ittraining

http://ittrainingsolutions.webs.com/

http://erwinglobio.sulit.com.ph/

For your IT Training needs

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Prof. Erwin M. Globio, MSITIT Training SpecialistMobile Number: 09393741359

09323956678Email Address: [email protected] Id: erwinglobio