chapter 2- testing through out software life cycle

7/28/2019 Chapter 2- Testing Through Out Software Life Cycle

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Testing Throughout the Software Life Cycle


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ISTQB syllabus 2010 Testing Throughout the Software Life

Cycle

Terms to Remember

Know your level


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ISTQB can be done :

by everyone who are involved insoftware testing

who wants a basic understanding ofsoftware testing

Basic level for higher-level software

testing qualification.


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The new syllabus of version 2010 iseffective 30-Mar-2010

Learning objectives are classified asfollows:

K1: remember, recognize, recall

K2: understand, explain, give reasons, compare,classify, categorize, give examples, summarize

K3: apply, use

K4: analyze


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Explain the Test Levels Identify the Test types

Describe Maintenance Testing


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Test Design finds faults

Faults found early are cheaper to fix

Most significant faults found first

Faults prevented, not built in Changing requirements caused by Test Design

EARLY TEST DESIGN HELPS TO BUILD

QUALITY, STOPS FAULTMULTIPLICATION


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Verification :

Process of evaluating a system or component to determinewhether the products of the given development phaseconditions imposed at the start of the phase [ BS7925 -1 ]

Validation :Determination of the correctness of the products of

software development with respect to the user needs and

requirements [ BS7925 -1 ]


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In any life cycle model, there are several characteristics of goodthings. For every development activity , there is a corresponding testing activity.

Each test level has test objectives specific to that level

The analysis and design tests for a given test level should begin during

the corresponding development activity . Testers should be involved in reviewing documents as soon as drafts are

available in the development life cycle

Testers can be combined or reorganized depending on the nature ofthe project

For the integration and commercial off-the-shell { COTS} software

product into a system, the purchaser may perform integrationtesting at the system level and acceptance level


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Each test level can have specific :

Objective

Test Object

Defect / Failures Found

Approach Levels of Testing Available

Component Testing

Integration Testing

System Testing and

Acceptance testing


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Component Testing

Lowest Level of Testing

Tested in isolation

Most thorough look at detail :

Error handling

Interface

Usually done by programmer, it is also known as unit, module,

program testing , usually carried out in development environment

Defects found are fixed without formal recordings of incidents


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Integration testing tests interfaces between components, interactions withdifferent parts of a system, such as operating system, file system, hardware orinterfaces between systems.

More than one [tested ] Component

Communication between components

What the set can perform that is not possible individually.

Nonfunctional aspects if possiblen

Few types of Integration Testing are :

Bing Bang , Top Down & Bottom Up Testing


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In big bang integration testing individual modules of the programs are not

integrated until every thing is ready. This approach is seen mostly in inexperienced

programmers who rely on Run it and see approach. In this approach, the program is

integrated without any formal integration testing, and then run to ensures that all

components are working properly

. Disadvantages :

Defects present at the interfaces of components are identified at very last stage.

It is very difficult to isolate the defects found, as it is very difficult to tell whether

defect is component or interface.

There is some high probability of missing some critical defects which might surface

in production.

It is very difficult to make sure that all test cases for integration testing are covered.


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Baseline 0 : Tested component

Baseline 1 : Tested 2 components

Baseline 2 : Tested 3 components and so on.

Advantages are :o Easier fault location and fix

o

Easier recovery from disaster / problemso Interfaces should have been tested in components tests , but add to

tested baseline


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The Major steps are :1. The main control module is used as a test driver and stubs

all are substituted for all components directly subordinate

to the main module.

2 Depending on the integration approach subordinate stubs are

replaced once a time with actual components.

3 Tests are conducted as each component is integrated

4 Stubs are removed and integrations are moves downward in the

Program structure.

Advantages : Can verify major control or decision points early

Disadvantage : Stubs are required when perform the integration testing, andgenerally , develop stubs is very difficult


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Major Steps:

1.Low-Level components will be tested individually first.

2. A driver ( a control program for testing )is written to coordinate

test cases

3. Input and output

4. The driver is removed and integration moves upward in the

program structure

5. Repeat the process until all components are included in the test.

Advantage : Compared with stubs, drivers are much easier to developDisadvantage : Major control and decision problems will be identified later inthe testing process


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Goal of UAT is to establish confidence in the system, parts of the

system or specific non-functional characteristic of the system.

Final Stage of Validation

Customer (user ) should perform or be closely involved

Customer can perform any test they wish, usually based on

their business processes.

Final user sign off.

Approach Mixture of scripted and unscripted testing.


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Types of Acceptance Testing

Operational ( Acceptance ) Testing. Acceptance of the system by the system administrators,

including : Testing of back up / restore

Disaster recovery

User Management

Maintenance Tasks

Contract Acceptance testing : Agreed contract definition stage

Acceptance criteria defined and agreed May not have kept up to date with changes.


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Testing by { potential } customers orrepresentatives of your market.

When software is stable

Use the product in a realistic way in its operationalenvironment.

Comments back on the product

Faults found How the product meet their expectations ?

Improvement / Enhancements Suggestions ?


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Which Statement is correct ?

System testing may investigate both functional and non functionalrequirement of the system

System testing only investigate both functional and optionally nonfunctional requirement of the system

System testing should investigate both functional and non functionalrequirement of the system

System testing only investigate both functional and non functionalrequirement of the system


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Functions are What the system does

Functional (Black Box) tests considers theexternal behavior of the software.

Functional tests are based on functions and featuresand their interpretability with specific systems


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Testing of how the system works.

Non functional testing includes , but it is not limited to,performance testing, load testing, stress testing, usabilitytesting, maintainability testing, reliability testing and portable

testing.

Non functional testing describes the test required to measurecharacteristic of system of software that can be quantified ona varying scale , such as response time for performance testing.

Most non functional tests are defined in the quality model.


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Non functional testing includes

Testing to see, whether the system does not functioncorrectly.

Testing the quality attributes of the system includingreliability and usability.

Gaining user approval for the system

Testing a system feature using only the softwarerequired for that function.


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Structural techniques are best used afterspecificationbased techniques, to measure thecoverage of a type of structure

White box, Statement testing, Branch / Decisiontesting, Data flow testing, Branch condition testing,Branch condition combination testing are somestructural test techniques.


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Test to confirm whether original defect has beensuccessfully removed.

Retesting an already tested program after modification,

to discover any new defects introduced as a result ofchange is known as Regression testing.

Extent of Regression Testing is based on the risk ofnot finding any new defects in software, which was

working previously. Regression test suites are run many times and

generally evolve slowly, so regression testing is astrong candidate for automation


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Which is not a level in V model testing ?

1. System Testing

2. Integration Testing

3. Regression Testing

4. Unit Testing

Answer : 3.

Simulators are used in which type of testing ?

1. Integration Testing

2. System Testing

3. Component Testing

4. None of the above

Answer : 1


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Which ONE of the following testing is TRUE.

1. Re testing and Regression testing together showthat a defect has been fixed and that the fix has nothad an adverse effect elsewhere

2. Re-testing involves running a test again to makesure the observed result was as previouslyrecorded.

3. Regression Testing is carried out only when thesoftware is changed.

4. Regression testing involves re-running a test thatfailed to make sure a defect has been fixed.


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All the Best !!

chapter 2- testing through out software life cycle

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