Introduction to Software Testing

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Module Objectives• Introduction to Software Testing• Importance of Software Testing• Verification and Validation• Software Test Lifecycle• Testing Process

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Goal of testing

The goal of a software tester is:• To find bugs• To find them as early as possible• & make sure they get fixed

Testing is a means to:• Find bugs• Provide confidence and information• Even prevent defects

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Why is testing needed A defect in the software has a root cause, while the effect of defect is

seen as impact by the different stake holders. Testing is part of overall Quality Assurance – It covers the Quality

Control aspect of ensuring Quality A fault doesn't necessarily result in a failure, but a failure can only occur if a

fault exists. To avoid a failure you must find the fault. Software testing may be required for compliance with contractual or legal requirements When is testing complete?• Actually never• However for practical reasons it is stopped after considering the

risks involved, time and budget constraints

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Why is testing neededWhy is testing needed Complexity of software makes it error prone Untested or weakly tested software can cause losses in real life. Eg:• Disney’s Lion King – 1994 – 1995- The software did not work on

the most common systems that the public had.• Intel Pentium Floating-Point Division Bug – 1994 – Intel took a

charge of more than $400 million to cover the costs of replacing

bad chips• NASA Mars Polar Lander – 1999 – Malfunction due to an

unexpected setting of a single data bit• Patriot missile defense system – 1991 – A software bug caused

the tracking system to be inaccurate after 14 hrs of operation

Software bugs can cause harm to a person, to the environment or to a

company

Testing Profession

Who makes a Good tester

The tester’s mindset must have the below mentioned attributes

Keen Observation Questioning Skills “Never give-up” attitude Interpersonal Skills

The V-Model

The V-model can be said to have developed as a result of the evolution of software testing. Various testing techniques were defined and various kinds of testing were clearly separated from each other which led to the waterfall model evolving into the V-model. The tests in the ascending (Validation) hand are derived directly from their design or requirements counterparts in the descending (Verification) hand. The ‘V’ can also stand for the terms Verification and Validation.

SDLC and STLC

The Testing Process

Project Initiation

Test Strategy and Planning

Test Environment setup

Test Case Designing

Test Execution

Defect Reporting and Tracking

Project closure

Test Cycles

References• http://knol.google.com/k/istqb-certification-answers-of-all-tests-chapter-1-6#• http://9th-direction.com/ISTQB/ISTQB-Question-Paper-Dump-6.pdf • http://istqb.org/download/attachments/2326555/Foundation%20Level%20Syllabus

%20(2010).pdf • http://istqb.patshala.com/

Thank you