Software Quality Engineering & Testing Basics

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Software Quality

Engineering & TestingBasics


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Software Quality Engineering & Testing Basics

Contents

Part 1: Classic SDLC Models ..

Part 2: Software Testing ..

Part 3: Software Quality Engineering ..


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Part 1

Classic SDLC Models


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The classic SDLC Models:

4. Big Bang

5. Code and fix

6. Waterfall7. Spiral


Part 1 : ass c DLModels

P 1 DL


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Big-Bang Model :

The Approach

People+Money+Energy=PerfectSoftware or Nothing!

Advantages

Simple, needs less planning, lessformal development process

DisadvantagesNo formal testing activities, cantmonitor, high risk


P 1 DL


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Code and Fix Model :

The Approach

Informal specification loop ofcode and fix till enough-is-enough

decisionRelease

Advantages

Little planning and documentation

work.

Disadvantages

Hard to manage the testing


P t 1 DL


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Waterfall Model :

The Approach

Discrete phases, a review aftereach phase will decide to move

next or stay at this phase till itsready.

Advantages

Easy to test (clear requirements)

DisadvantagesHigh bugs fixing cost (bugscreep), customer is far from thistill the end


P t 1 DL


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Spiral Model :

The Approach

Round1 (Waterfall Prototype)

Evaluate Round1

Round2 (Waterfall Prototype)

Loop

Advantages

Easy to test, the customer is

tightlyinvolved

Disadvantages

Need risk-assessments expertise



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Part 2

Software Testing


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Part 2 : Software Testing

What is software testing?

A quality control activity aimed atevaluating a software item against thegiven system requirements.



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What is software testing?

A quality control activity aimed atevaluating a software item against thegiven system requirements.


Testing

isaQC

activity


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What is the V&V?

Verification: Confirming that something(software) meets its specification.

Validation: Confirming that it meetsthe users requirements.

The two major V&V activities arereviews, and testing. *



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What is the V&V?

Verification: Confirming that something(software) meets its specification

Validation: Confirming that it meetsthe users requirements.

The two major V&V activities arereviews, and testing.


Testi

ngis

aparto

fV&V

activ

ities


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What should the tester do?

Find the bugs

Find them early

Make sure that they have beenfixed



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What should not the tester do?

Fix the bugs! *

Trust the others!

Test with no requirements! Not to report the obvious bugs!

Test with good faith!



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What are the testing types?

1. Static Testing

Testing a software that is notrunning.

2. Dynamic Testing

Test running software.

Unit (white box), Functional,

Integration, System, Regression,Volume, Load, Stress Integration,Usability, Localization, Live(Production), Compatibility, Smoke,Ad-hoc, User Acceptance



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2. Dynamic Testing (Contd)

Unit Test: A test of one component of the system.

White Box Test:Testing software with complete knowledge of itsinternal code and logic.

Black Box Test:Testing software based on output only withoutany knowledge of its internal code or logic.

Gray Box Test:Testing software with some knowledge of itsinternal code or logic.

Functional Test:Testing functional requirements of software,such as menus and key commands.

System Test: Overall testing in the user environment.



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Acceptance Test:The test performed by end users to approve thesystem.

Alpha Test:The first testing of a product in the production

environment before going live.Beta Test:Testing done by end users.

Volume testing: testing a software application for a certain datavolume.*

Load testing: creating demand on a system or device andmeasuring its response.

Stress testing: determine the stability of a given system or entity.

Compatibility testing: measures how well the system operates ondifferent operating environment. *Software Quality Engineering & Testing Basics


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Recovery Test:Testing a system's ability to recover from ahardware or software failure.

Accessibility testing: measure how well the system interface

serve users with disabilities.*

Negative Test: Using invalid input to test a program's errorhandling.

Regression testing:Testing to make sure that the fix is working

as expected.

Ad Hoc Test: Informal testing without a test case.

Automated Test: Using software to test software.*



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What is the bug ?

Things the software does that while itis not supposed to do, OR somethingthe software doesn't while it issupposed to.



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What are the differencebetween the bug severity andpriority?Priority means how urgently bug isneeded to fix.

Severity means how badly it harmsthe system.



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How to report a bug?


Report the pattern not anexample.

Dont describe what's wrong,only!

Be direct to the point (dont tell astory!).

Report the bug, but not how tosolve it.

Dont mix between priority and

severity.


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How to report a bug? (Contd)


Dont use: CAPS, red letters,red circles, ! , ?.

Dont use your personaljudgment.

Write with the fixer language, notwith yours.

Minimize the options.

Dont use the word Sometimes.


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How to report a bug? (Contd)


Dont group the bugs.

Dont update the bug

description.

Dont update the bug severity.


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When not to fix a bug?


Its too risky to fix it.

Its not worth fixing.

There is no enough time.

Its not really a bug.


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What are the testing activities?


1. Test Plan.

2. Test Analysis.

3. Test Design.4. Test Cases Development.5. Test Cases Execution.6. Test Reporting.

7. Bugs Reporting.8. Releasing reporting.

9. User Acceptance Testing.


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When to stop testing?


1. Deadline has be been reached.

2. Test cases completed with

passed percentage.

3. End of test budget.


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Part 3

Software Quality


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Part 3 : Software Quality

What is 'Software QualityAssurance?


Software QA involves the entiresoftware development PROCESS- monitoring and improving theprocess, making sure that anyagreed-upon standards andprocedures are followed, andensuring that problems are

found and dealt with. It isoriented to 'prevention'.

f li


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What is the Quality Software?


Quality software is fairly bug-free, delivered on time andwithin budget, meetsrequirements and/orexpectations, and ismaintainable. However, qualityis obviously a subjective term.


P 3 S f Q li


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What are the main qualityattributes?


Availability: Is it available when and where I need touse it?

Efficiency: How few system resources does itconsume?

Flexibility: How easy is it to add new features?

Installability: How easy is it to correctly install theproduct.

Interoperability: How easily does it interconnect withother systems?

Maintainability: How easy it is to correct defects or

make changes?


P 3 S f Q li


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Reliability: How long does it run before causing afailure?

Reusability: How easily can we use components inother systems?

Testability: Can I verify that it was implementedcorrectly?

Usability: How easy is it for people to learn or to use?

Performance: the response time, utilization, andthroughput behavior of the system.


P t 3 S ft Q lit


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Security: systems ability to resist unauthorizedattempts at usage or behavior modification, while stillproviding service to authorized users.


P t 3 S ft Q lit


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What are the types of softwarereviews?


1. Peer Review

2. Walkthrough

3. Inspection

Moref

ormal


P t 3 S ft Q lit


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What is the characteristics of Peerreviews?


Informal.

Audience: Owner(author) and peer(s)of similar expertise (no managers).

It require guidelines and checklist.


P t 3 S ft Q lit


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What is the characteristics of the

walkthrough?


More formal.

Audience: 3-5 , at least 1 senior, the

owner act as a reader and recorder.

The owner should send a copy of thingsthat need review prior to the meeting.

Reader should write a report with thefeedback and how to address it.

2nd meeting can be conducted to followup.


P t 3 S ft Q lit


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Inspection?


The most formal.

Audience: typically 3-8 people including

a moderator, reader, and a recorder totake notes.

The reader should not be the owner.

The owner should send a copy of thingsthat need review prior to the meeting.

Each Inspectors should review the code fora different perspective.


P t 3 S ft Q lit


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Inspection? (Contd)


After the inspection meeting the moderatorcall for another meeting to discuss thefeedback and how the owner will address

them.

Require training.


P t 3 S ft Q lit


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Quality standards and auditingorganizations


ISO (International Organization forStandardization).

CMMI (Capability Maturity ModelIntegration).

IEEE (Institute of Electrical and ElectronicsEngineers).


Part 3 Software Quality


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ISO 9001:2000


ISO 9001 is a series of documents that definerequirements for the Quality ManagementSystem Standard. ISO 9001 is one of thedocuments in this set; it contains the actualrequirements an organization must be incompliance with to become ISO 9001Registered.




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Why do companies want ISO 9001:200


Many organizations decide to Implement ISO9001 and obtain registration because itassures customers that the company has a

good Quality Management System (QMS) inplace. An organization with an effective QMSwill typically meet customer expectationsbetter than an organization that does nothave an effective QMS. Many organizations

require their suppliers to have ISO 9001Registration.




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What is CMMI ?


Capability Maturity Model Integration (CMMI)is a process improvement approach thatprovides organizations with the essential

elements of effective processes. It can beused to guide process improvement across aproject, a division, or an entire organization.CMMI provide guidance for quality processes,and provide a point of reference for appraising

current processes.




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What are the 5 levels of CMMI ? (Contd


Level One Initial

Company has no standard process forsoftware development. Nor does it have aproject-tracking system that enables

developers to predict costs or finish dates withany accuracy.

Level Two - Managed

Company has installed basic software

management processes and controls. Butthere is no consistency or coordination amongdifferent groups.




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Level Three Defined

Company has pulled together a standard setof processes and controls for the entireorganization so that developers can move

between projects more easily and customerscan begin to get consistency from differentgroups.

Level Four Quantitively Managed

In addition to implementing standardprocesses, company has installed systems tomeasure the quality of those processes acrossall projects.




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Level Five - OptimizedCompany has accomplished all of the aboveand can now begin to see patterns inperformance over time, so it can tweak itsprocesses in order to improve productivityand reduce defects in software developmentacross the entire organization.




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What is the IEEE ?

The Institute of Electrical and ElectronicsEngineers" (IEEE) is a non-profit organizationthat develops, defines, and reviewselectronics and computer science standards.


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Software Quality Engineering & Testing Basics