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System Testing

by

D.MOHANA GOWRI

II MS(CS)

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System Testing

Unit & Integration Testing

Objective: to make sure that the

program code implements thedesign correctly.

System Testing Objective: to

ensure that the software does

what the customer wants it to

do.

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Causes of Software Faults

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System Testing Process

Function Testing: the system must performfunctions specified in the requirements.

Performance Testing: the system must satisfysecurity, precision, load and speedconstrains specified in the requirements.

Acceptance Testing: customers try the system(in the lab) to make sure that the systembuilt is the system they requested.

Deployment Testing: the software is deployedand tested in the production environment.

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System Testing Process

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Build & Integration Plan

- Large complex system is very hard totest.

+ We can devise a build & integration

plan defining subsystems to be builtand tested such that we aremanaging a less complex entity.Such subsystems usually correspondto increments in system scope &

functionality and are called spins.Example: Microsofts Synch & Stabilize

approach.

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Build & Integration Plan Contd

Each spin is identified including itsfunctionality and testing schedule.

If the test of spin n succeeds but the

problem arises during the testing ofspin n+1 we know that the faultcomes from components /functionality introduced in spin n+1.

Accounting System Example: spin 0

basic accounting operations aretested; spin 1 accounting with dataauditing tested; spin 2 access usercontrol is tested, etc.

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Configuration Management

Module-based systems can beshipped in various configurationsof components defining the

systems functionality andperformance.

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Regression Testing

Regression testing ensures that no new faults areintroduced when the system is modified, expandedor enhanced as well as when the previouslyuncovered faults are corrected.

Procedure:

1. Insert / modify code2. Test the directly affected functions

3. Execute all available tests to make sure that nothingelse got broken

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Test Team

Testers: devise test plans, design,organize and run tests

Analysts: assist testers, provide

guidance for the process verificationas well as on the appearance of thetest results

Designers: assist testers, provideguidance for testing components and

software architectureUsers: provide feedback for the

development team

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Function Testing

Thread Testing: Verifying a narrow set ofactions associated with a particular function

Test process requirements

Test plan including the stopping criteria High probability for detecting a fault

Use of independent testers

The expected actions and the expectedoutput must be specified

Both valid and invalid input must be tested

System must not be modified in the testingprocess (or to make testing easier)

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Performance Testing

Load / Stress Testing: large amount ofusers / requests

Volume Testing: large quantities of data

Security Testing: test access,authentication, data safety

Timing Testing: for control and event-driven systems

Quality / Precision Testing: verify theresult accuracy (when applies)

Recovery Testing: verify recovery fromfailure process (when applies)

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Acceptance Testing

The purpose is to enable customers and users to determine ifthe system built really meets their needs andexpectations.

Benchmarking: a predetermined set of test casescorresponding to typical usage conditions is executedagainst the system

Pilot Testing: users employ the software as a small-scaleexperiment or in a controlled environment

Alpha-Testing: pre-release closed / in-house user testing

Beta-Testing: pre-release public user testing

Parallel Testing: old and new software are used together andthe old software is gradually phased out.

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THANK YOU