1. SOFTWARE TESTING

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Objectives
After completion of this chapter you will be able to:
• Explain what is Software Testing
• Understand the Software Testing objectives
• Understand the test plan
• Define white box & Black box testing
• Explain different test levels
• Explain the concepts of test cases suites,
scripts& scenarios
• Define and explain the testing cycle

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• Software Testing is the process used to help to identify the
correctness, completeness, security, and quality of
developed computer software.
• Testing is a process of technical investigation, performed
on behalf of stakeholders, that is intended to reveal quality-
related information about the product.
• Testing can never completely correct all the time.So it will
be continued.
• Software testing should be distinguished from the discipline
of Software Quality Assurance (SQA), which encompasses
all business process areas, not just testing.
Introduction

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• In SQA, software process specialists and
auditors take a broader view on software and its
development.
• They examine and change the software
engineering process itself to reduce the amount
of faults that end up in the code or deliver faster.
Introduction contd..

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Testing objectives
Introduction contd..
• Testing is a process of executing a program with
the intent of finding an error.
• A good test case is one that has a high
probability of finding an as yet undiscovered
error.
• A successful test is one that uncovers an as yet
undiscovered error.
• Testing demonstrates that the software appears
to be working as stated in the specifications.
• It cannot show the absence of defect , it can only
show that software defects are present.

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Roles in software testing
Introduction contd..
• Software testing is a process which is done by
software testers.
• Until the 1950s the term software tester was
used generally, but later it was also seen as a
separate profession.
• It has been established different roles:
• Test lead
• Tester
• Test designer
• Test automator
• Test administrator

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Roles in software testing
Introduction contd..
• Participants of testing team
• Tester
• Developer
• Customer
• Information Service Management He is the
person who collects information from the
customer
• Senior Organization Management
• Quality team

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When Testing should start
Introduction contd..
• In the early stage of testing life cycle it reduces the errors.
• The goal of Software Tester is to find bugs, find them as
early as possible, and make them sure they are fixed.
• The number one cause of Software bugs is the
Specification.
• The next largest source of bugs is the Design, that’s where
the programmers lay the plan for their Software.
• Coding errors is another familiar error in software testing .
• Typically these can be traced to the Software complexity,
poor documentation, schedule pressure or just plain dump
mistakes.

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When to Stop Testing
Introduction contd..
• It is difficult to determine.
• There are common factors in deciding when to stop
testing:
• Deadlines (release deadlines, testing deadlines.)
• Test cases completed with certain percentages
passed
• Test budget depleted
• Coverage of code/functionality/requirements reaches
a specified point
• The rate at which Bugs can be found is too small
• Beta or Alpha Testing period ends
• The risk in the project is under acceptable limit

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Test Plan
• The test strategy identifies multiple test levels,
which are going to be performed for the project.
• Activities at each level must be planned well in
advance and it has to be formally documented.
• Based on the individual plans only, the individual
test levels are carried out.

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Test plan contd..
• A sample Test Plan Outline is shown below:
•Testing tasks
•Environmental needs
•Responsibilities
•Staffing & Training
•Schedule
•Resources
•Risks & Contingencies
•Approvals
•Background
•Introduction
•Assumptions
•Test Items
•Features to be tested
•Features not to be tested
•Approach
•Item pass/fail criteria
•Suspension/Resumption criteria
•Test deliverables

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White box & black-box testing
• White box and black box testing are terms used to
describe the point of view a test engineer takes when
designing test cases.
• Black box being an external view of the test object
• white box being an internal view.
• White box testing uses an internal perspective of the
system to design test cases based on internal structure.
• White box requires programming skills to identify all paths
through the software.
• Black box testing takes an external perspective of the test
object to derive test cases.
• The test designer selects valid and invalid input and
determines the correct output. There is no knowledge of
the test object's internal structure.

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Test levels
• There are four level :
• Unit testing
• Integration testing
• System testing
• Acceptance testing

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• Unit testing is a procedure used to validate that
individual units of source code are working properly.
• Unit is the smallest testable part of an application
• In procedural programming a unit may be an individual
program, function, procedure, web page, menu etc,
while in object-oriented programming, the smallest unit
is always a Class; which may be a base/super class,
abstract class or derived/child class.
Test levels contd..

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The test levels contd..
• Integration testing exposes defects in the
interfaces and interaction between integrated
components (modules).
• Integration testing is the phase of software
testing in which individual software modules are
combined and tested as a group.
• It follows unit testing and precedes system
testing.

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The test levels contd..
• System testing tests an integrated system to
verify/validate that it meets its requirements.
• System testing is testing conducted on a
complete, integrated system to evaluate the
system's compliance with its specified
requirements.
• System testing falls within the scope of black
box testing, and as such, should require no
knowledge of the inner design of the code or
logic.

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• Acceptance testing can be conducted by the client. It
allows the end-user or customer or client to decide
whether or not to accept the product.
• In engineering and its various sub disciplines,
acceptance testing is performed
• Acceptance testing can be divide in two parts :
• Alpha testing
• Beta testing
The test levels contd..

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Test cases, suites, scripts and
scenarios
• In software engineering, the most common
definition of a test case is a set of conditions or
variables under which a tester will determine if a
requirement or use case upon an application is
partially or fully satisfied.

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Structure of test case
• Test cases consist three main parts :
•Results
•Expected results
•Actual result
•Activity
•Testing environment/configuration
•Initialization
•Finalization
•Actions
•Input data description
•Information
•Identifier
•Test case
owner
•Name
•Identifier of
requirement
•Purpose
•Dependencies

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Test cases, suites, scripts and
scenarios contd..
• Test Script
• A test script is a short program written in a
programming language used to test part of the
functionality of a software system.
• Test Suite
• The most common term for a collection of test
cases is a test suite.
• Scenario
• Scenario testing is a software testing activity. It uses
scenario tests, or simply scenarios, which are based
on a hypothetical story to help a person think
through a complex problem or system.

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Testing cycle
• Software testing is maintain through a chain of cycle
The stages of cycle are as follows:
• Requirements Analysis:
• Design phase,
• Test Planning
• Test Development:
• Test Execution
• Test Reporting
• Retesting the Defects