SOFTWARE QUALITY
ASSURANCE
LECTURE 01 : WEEK 01
SEN 460
: SPRING 2015
TEXT AND REF. BOOKS
Text Book:
Software Quality Engineering by Jeff Tian IEEE
Reference Book:
Software Quality Engineering A practitioners Approach IEEE
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MS (Software Engineering)
BCIT(Ned University of Engineering and Technology) Email : [email protected]
Presented by: Sumeera Hashmi
SOFTWARE QUALITY
ASSURANCE ?
Quality ! What Is It ?
Quality Not a single idea
many aspects
Popular View
In everyday life, usually thought of as intangible, can be
felt or judged, but not weighed or measured
“I know it when I see it” - implies that it cannot be
controlled, managed, or quantified
The standard of something measured against other
Why Software quality?
Quality a critical attribute of software product
Financial Health Life loss
Evolving Domain of SQ from technical
Why Software quality?
Center of gravity shifts
from creating
an engineering solution to satisfying the
stakeholders.
Trend
within
the
community
of
Why Software quality?
Critical word
“satisfaction”
It covers both
Functional perception of the software
solution
Why Software quality?
Why software?
In contemporary social life software, systems
and services rendered by software are omnipresent, beginning with the watches to nuclear electricity plant.
Why quality?
Because if these instances of software work
Why Software Quality
Assurance?
A belief that
Adherence to development process, as in
manufacturing, will lead to a quality product.
Alternatively
Process improvement will lead to a quality
Software Quality Challenge
For user a software product is more and
more corresponds to a black box to
satisfy their business needs.
Consequences
Business needs drive quality software development. Stakeholder moves to the position of a car buyer and
Result
User’s perspective of the end product is
the final judgement corresponds to
Required functionality Required quality
Absence of any one leads to a painful
What is Software Quality?
Software Quality is:
The degree to which a system, component,
or process meets specified requirements [Philip B. Crosby’s definition, 1979]
The degree to which a system, component
or process meets customer or user needs or expectations.
What exactly constitutes the
Quality?
Hot debate why?
No common agreement to what it
means, is it
Customer Value
Defect level
Perspectives by Kitchenham & Pfleeger
1.
Transcendental perspective
Something towards which we are striving as an
ideal, but may never implement completely
2.
User perspective
Appropriateness of the product for a given
context of use
3.
Manufacturing Perspective
Perspectives by Kitchenham & Pfleeger
Product perspective
Inherent characteristics of the
product(measured in terms of defect rate ,# bugs per line of code)
Final perspective
Different perspectives of quality may have a
Quality Assurance vs Quality
Control
Definition
QA is a set of activities for ensuring quality
in the processes by which products are developed
QC is a set of activities for ensuring quality
Quality Assurance vs Quality
Control
Focus on
QA aims to prevent defects with a focus on
the process used to make the product. It is a proactive quality process.
QC aims to identify (and correct) defects in
Quality Assurance vs Quality
Control
What
QA is prevention of quality problems through
planned and systematic activities including documentation.
QC is the set of activities or techniques used
Quality Assurance vs Quality
Control
Tools and
QA is managerial tool.
QC is corrective tool
Orientation
QC is product oriented
QA in Software Project development
Defect Prevention in early stages
Goal
Error blocking to avoid data propagation and increasing cost over time to
or successive phases to fix defects
Error Source
Conceptual mistakes by designers and programmers Unfamiliarity with the product domain
Techniques
Inspection of requirement documents and product specification
limitations
Dynamic problems may only become apparent during execution
QA in Software Project
development
limitations
Dynamic problems may only become apparent during execution
Inter-dependency only becomes apparent with the implementation of
related modules
Defect Removal
Because of the early phase testing limitations defect removal
techniques such as testing is performed in the middle to late phases
Failure Prevention and containment
Fault tolerance and safety assurance are typically focus of
Defect Handling
Defect Resolution
Each discovered defect is corrected or taken care of through appropriate channels
Corrected or Fixed Defects
Each defect needs to be verified to ensure failure free executions, under the same execution condition
Not-Corrected Defects
Defect Handling
Re-classification
If a defect is later re-classified as not a defect, a justification needs to be given and decision agreed upon by the person who reclassify, the tester who reported the defect and all other people.
Deferred defects
Support Activities for Defect Resolution
Defect logging
Initial reporting and logging of defects. It
ensures that a record is kept for each
defect.
Defect Tracking
Monitors and record what happened to each
Exercise for next class
A complete study of what tools are
being used for defect tracking and
monitoring.
At least one tool should be completely
Any Questions !!!
END OF LECTURE
