Software testing

Mukesh Kumar ppimt.edu.in
CSE 6th
Sem. ppimt.org
Software Testing
This section describes the different types of testing which may be used to test a Software during
SDLC.
Manual testing
This type includes the testing of the Software manually i.e. without using any automated tool or any
script. In this type the tester takes over the role of an end user and test the Software to identify any
un-expected behavior or bug. There are different stages for manual testing like unit testing,
Integration testing, System testing and User Acceptance testing.
Testers use test plan, test cases or test scenarios to test the Software to ensure the completeness of
testing. Manual testing also includes exploratory testing as testers explore the software to identify
errors in it.
Automation testing
Automation testing which is also known as Test Automation, is when the tester writes scripts and
uses another software to test the software. This process involves automation of a manual process.
Automation Testing is used to re-run the test scenarios that were performed manually, quickly and
repeatedly.
Apart from regression testing, Automation testing is also used to test the application from load,
performance and stress point of view. It increases the test coverage; improve accuracy, saves time
and money in comparison to manual testing.
What to automate?
It is not possible to automate everything in the Software; however the areas at which user can make
transactions such as login form or registration forms etc, any area where large amount of users. can
access the Software simultaneously should be automated.

CSE 6th
Sem. ppimt.org
Furthermore all GUI items, connections with databases, field validations etc can be efficiently tested
by automating the manual process.
When to automate?
Test Automation should be uses by considering the following for the Software:
 Large and critical projects.
 Projects that require testing the same areas frequently.
 Requirements not changing frequently.
 Accessing the application for load and performance with many virtual users.
 Stable Software with respect to manual testing.
 Availability of time.
How to automate?
Automation is done by using a supportive computer language like vb scripting and an automated
software application. There are a lot of tools available which can be use to write automation scripts.
Before mentioning the tools lets identify the process which can be used to automate the testing:
 Identifying areas within a software for automation.
 Selection of appropriate tool for Test automation.
 Writing Test scripts.
 Development of Test suits.
 Execution of scripts.
 Create result reports.
 Identify any potential bug or performance issue.
Software testing tools
Following are the tools which can be use for Automation testing:
 HP Quick Test Professional
 Selenium
 IBM Rational Functional Tester
 SilkTest

CSE 6th
Sem. ppimt.org
 TestComplete
 Testing Anywhere
 WinRunner
 LaodRunner
 Visual Studio Test Professional
 WATIR
There are different methods which can be use for Software testing. This chapter briefly describes
those methods.
Black Box Testing
The technique of testing without having any knowledge of the interior workings of the application is
Black Box testing. The tester is oblivious to the system architecture and does not have access to the
source code. Typically, when performing a black box test, a tester will interact with the system's user
interface by providing inputs and examining outputs without knowing how and where the inputs are
worked upon.
Advantages Disadvantages
 Well suited and efficient for large code segments.
 Code Access not required.
 Clearly separates user's perspective from the developer's
perspective through visibly defined roles.
 Large numbers of moderately skilled testers can test the
application with no knowledge of implementation,
programming language or operating systems.
 Limited Coverage since only a selected
number of test scenarios are actually
performed.
 Inefficient testing, due to the fact that the
tester only has limited knowledge about an
application.
 Blind Coverage, since the tester cannot
target specific code segments or error
prone areas.
 The test cases are difficult to design.

CSE 6th
Sem. ppimt.org
White Box Testing
White box testing is the detailed investigation of internal logic and structure of the code. White box
testing is also called glass testing or open box testing. In order to perform white box testing on an
application, the tester needs to possess knowledge of the internal working of the code.
The tester needs to have a look inside the source code and find out which unit/chunk of the code is
behaving inappropriately.
 As the tester has knowledge of the source code, it
becomes very easy to find out which type of data
can help in testing the application effectively.
 It helps in optimizing the code.
 Extra lines of code can be removed which can
bring in hidden defects.
 Due to the tester's knowledge about the code,
maximum coverage is attained during test
scenario writing.
 Due to the fact that a skilled tester is needed to
perform white box testing, the costs are increased.
 Sometimes it is impossible to look into every nook
and corner to find out hidden errors that may create
problems as many paths will go untested.
 It is difficult to maintain white box testing as the use
of specialized tools like code analyzers and
debugging tools are required.
Grey Box Testing
Grey Box testing is a technique to test the application with limited knowledge of the internal workings
of an application. In software testing, the term the more you know the better carries a lot of weight
when testing an application.
Mastering the domain of a system always gives the tester an edge over someone with limited
domain knowledge. Unlike black box testing, where the tester only tests the application's user
interface, in grey box testing, the tester has access to design documents and the database. Having
this knowledge, the tester is able to better prepare test data and test scenarios when making the test
plan.
 Offers combined benefits of black box and white
box testing wherever possible.
 Since the access to source code is not available,
the ability to go over the code and test coverage is

CSE 6th
Sem. ppimt.org
 Grey box testers don't rely on the source code;
instead they rely on interface definition and
functional specifications.
 Based on the limited information available, a grey
box tester can design excellent test scenarios
especially around communication protocols and
data type handling.
 The test is done from the point of view of the user
and not the designer.
limited.
 The tests can be redundant if the software designer
has already run a test case.
 Testing every possible input stream is unrealistic
because it would take an unreasonable amount of
time; therefore, many program paths will go
untested.
Black Box vs Grey Box vs White Box
S.N. Black Box Testing Grey Box Testing White Box Testing
1
The Internal Workings of an
application are not required to
be known
Somewhat knowledge of the internal
workings are known
Tester has full knowledge
of the Internal workings of
the application
2
Also known as closed box
testing, data driven testing
and functional testing
Another term for grey box testing is
translucent testing as the tester has
limited knowledge of the insides of
the application
Also known as clear box
testing, structural testing or
code based testing
3
Performed by end users and
also by testers and developers
Performed by end users and also by
testers and developers
Normally done by testers
and developers
4
Testing is based on external
expectations - Internal
behavior of the application is
unknown
Testing is done on the basis of high
level database diagrams and data
flow diagrams
Internal workings are fully
known and the tester can
design test data
accordingly
5
This is the least time
consuming and exhaustive
Partly time consuming and
exhaustive
The most exhaustive and
time consuming type of
testing
6 Not suited to algorithm testing Not suited to algorithm testing Suited for algorithm testing
7
This can only be done by trial
and error method
Data domains and Internal
boundaries can be tested, if known
Data domains and Internal
boundaries can be better
tested
There are different levels during the process of Testing. In this chapter a brief description is provided
about these levels.
Levels of testing include the different methodologies that can be used while conducting Software
Testing. Following are the main levels of Software Testing:

CSE 6th
Sem. ppimt.org
 Functional Testing.
 Non-Functional Testing.
Functional Testing
This is a type of black box testing that is based on the specifications of the software that is to be
tested. The application is tested by providing input and then the results are examined that need to
conform to the functionality it was intended for. Functional Testing of the software is conducted on a
complete, integrated system to evaluate the system's compliance with its specified requirements.
There are five steps that are involved when testing an application for functionality.
Steps Description
I The determination of the functionality that the intended application is meant to perform.
II The creation of test data based on the specifications of the application.
III The output based on the test data and the specifications of the application.
IV The writing of Test Scenarios and the execution of test cases.
V The comparison of actual and expected results based on the executed test cases.
An effective testing practice will see the above steps applied to the testing policies of every
organization and hence it will make sure that the organization maintains the strictest of standards
when it comes to software quality.
Unit Testing
This type of testing is performed by the developers before the setup is handed over to the testing
team to formally execute the test cases. Unit testing is performed by the respective developers on
the individual units of source code assigned areas. The developers use test data that is separate
from the test data of the quality assurance team.
The goal of unit testing is to isolate each part of the program and show that individual parts are
correct in terms of requirements and functionality.
LIMITATIONS OF UNIT TESTING
Testing cannot catch each and every bug in an application. It is impossible to evaluate every
execution path in every software application. The same is the case with unit testing.

CSE 6th
Sem. ppimt.org
There is a limit to the number of scenarios and test data that the developer can use to verify the
source code. So after he has exhausted all options there is no choice but to stop unit testing and
merge the code segment with other units.
Integration Testing
The testing of combined parts of an application to determine if they function correctly together is
Integration testing. There are two methods of doing Integration Testing Bottom-up Integration testing
and Top Down Integration testing.
S.N. Integration Testing Method
1
Bottom-up integration
This testing begins with unit testing, followed by tests of progressively higher-level combinations
of units called modules or builds.
2
Top-Down integration
This testing, the highest-level modules are tested first and progressively lower-level modules are
tested after that.
In a comprehensive software development environment, bottom-up testing is usually done first,
followed by top-down testing. The process concludes with multiple tests of the complete application,
preferably in scenarios designed to mimic those it will encounter in customers' computers, systems
and network.
System Testing
This is the next level in the testing and tests the system as a whole. Once all the components are
integrated, the application as a whole is tested rigorously to see that it meets Quality Standards. This
type of testing is performed by a specialized testing team.
System testing is so important because of the following reasons:
 System Testing is the first step in the Software Development Life Cycle, where the application is
tested as a whole.
 The application is tested thoroughly to verify that it meets the functional and technical specifications.
 The application is tested in an environment which is very close to the production environment where
the application will be deployed.
 System Testing enables us to test, verify and validate both the business requirements as well as the
Applications Architecture.
Regression Testing

CSE 6th
Sem. ppimt.org
Whenever a change in a software application is made it is quite possible that other areas within the
application have been affected by this change. To verify that a fixed bug hasn't resulted in another
functionality or business rule violation is Regression testing. The intent of Regression testing is to
ensure that a change, such as a bug fix did not result in another fault being uncovered in the
application.
Regression testing is so important because of the following reasons:
 Minimize the gaps in testing when an application with changes made has to be tested.
 Testing the new changes to verify that the change made did not affect any other area of the
application.
 Mitigates Risks when regression testing is performed on the application.
 Test coverage is increased without compromising timelines.
 Increase speed to market the product.
Acceptance Testing
This is arguably the most importance type of testing as it is conducted by the Quality Assurance
Team who will gauge whether the application meets the intended specifications and satisfies the
client.s requirements. The QA team will have a set of pre written scenarios and Test Cases that will
be used to test the application.
More ideas will be shared about the application and more tests can be performed on it to gauge its
accuracy and the reasons why the project was initiated. Acceptance tests are not only intended to
point out simple spelling mistakes, cosmetic errors or Interface gaps, but also to point out any bugs
in the application that will result in system crashers or major errors in the application.
By performing acceptance tests on an application the testing team will deduce how the application
will perform in production. There are also legal and contractual requirements for acceptance of the
system.
ALPHA TESTING
This test is the first stage of testing and will be performed amongst the teams (developer and QA
teams). Unit testing, integration testing and system testing when combined are known as alpha
testing. During this phase, the following will be tested in the application:
 Spelling Mistakes
 Broken Links
 Cloudy Directions
 The Application will be tested on machines with the lowest specification to test loading times and any
latency problems.

CSE 6th
Sem. ppimt.org
BETA TESTING
This test is performed after Alpha testing has been successfully performed. In beta testing a sample
of the intended audience tests the application. Beta testing is also known as pre-release testing.
Beta test versions of software are ideally distributed to a wide audience on the Web, partly to give
the program a "real-world" test and partly to provide a preview of the next release. In this phase the
audience will be testing the following:
 Users will install, run the application and send their feedback to the project team.
 Typographical errors, confusing application flow, and even crashes.
 Getting the feedback, the project team can fix the problems before releasing the software to the
actual users.
 The more issues you fix that solve real user problems, the higher the quality of your application will
be.
 Having a higher-quality application when you release to the general public will increase customer
satisfaction.
Non-Functional Testing
This section is based upon the testing of the application from its non-functional attributes. Non-
functional testing of Software involves testing the Software from the requirements which are non
functional in nature related but important a well such as performance, security, user interface etc.
Some of the important and commonly used non-functional testing types are mentioned as follows:
Performance Testing
It is mostly used to identify any bottlenecks or performance issues rather than finding the bugs in
software. There are different causes which contribute in lowering the performance of software:
 Network delay.
 Client side processing.
 Database transaction processing.
 Load balancing between servers.
 Data rendering.
Performance testing is considered as one of the important and mandatory testing type in terms of
following aspects:
 Speed (i.e. Response Time, data rendering and accessing)
 Capacity

CSE 6th
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 Stability
 Scalability
It can be either qualitative or quantitative testing activity and can be divided into different sub types
such as Load testing and Stress testing.
LOAD TESTING
A process of testing the behavior of the Software by applying maximum load in terms of Software
accessing and manipulating large input data. It can be done at both normal and peak load
conditions. This type of testing identifies the maximum capacity of Software and its behavior at peak
time.
Most of the time, Load testing is performed with the help of automated tools such as Load Runner,
AppLoader, IBM Rational Performance Tester, Apache JMeter, Silk Performer, Visual Studio Load
Test etc.
Virtual users (VUsers) are defined in the automated testing tool and the script is executed to verify
the Load testing for the Software. The quantity of users can be increased or decreased concurrently
or incrementally based upon the requirements.
STRESS TESTING
This testing type includes the testing of Software behavior under abnormal conditions. Taking away
the resources, applying load beyond the actual load limit is Stress testing.
The main intent is to test the Software by applying the load to the system and taking over the
resources used by the Software to identify the breaking point. This testing can be performed by
testing different scenarios such as:
 Shutdown or restart of Network ports randomly.
 Turning the database on or off.
 Running different processes that consume resources such as CPU, Memory, server etc.
Usability Testing
This section includes different concepts and definitions of Usability testing from Software point of
view. It is a black box technique and is used to identify any error(s) and improvements in the
Software by observing the users through their usage and operation.
According to Nielsen, Usability can be defined in terms of five factors i.e. Efficiency of use, Learn-
ability, Memor-ability, Errors/safety, satisfaction. According to him the usability of the product will be
good and the system is usable if it possesses the above factors.
Nigel Bevan and Macleod considered that Usability is the quality requirement which can be
measured as the outcome of interactions with a computer system. This requirement can be fulfilled
and the end user will be satisfied if the intended goals are achieved effectively with the use of proper
resources.

CSE 6th
Sem. ppimt.org
Molich in 2000 stated that user friendly system should fulfill the following five goals i.e. Easy to
Learn, Easy to Remember, Efficient to Use, Satisfactory to Use and Easy to Understand.
In addition to different definitions of usability, there are some standards and quality models and
methods which define the usability in the form of attributes and sub attributes such as ISO-9126,
ISO-9241-11, ISO-13407 and IEEE std.610.12 etc.
UI VS USABILITY TESTING
UI testing involves the testing of Graphical User Interface of the Software. This testing ensures that
the GUI should be according to requirements in terms of color, alignment, size and other properties.
On the other hand Usability testing ensures that a good and user friendly GUI is designed and is
easy to use for the end user. UI testing can be considered as a sub part of Usability testing.
Security Testing
Security testing involves the testing of Software in order to identify any flaws ad gaps from security
and vulnerability point of view. Following are the main aspects which Security testing should ensure:
 Confidentiality.
 Integrity.
 Authentication.
 Availability.
 Authorization.
 Non-repudiation.
 Software is secure against known and unknown vulnerabilities.
 Software data is secure.
 Software is according to all security regulations.
 Input checking and validation.
 SQL insertion attacks.
 Injection flaws.
 Session management issues.
 Cross-site scripting attacks.
 Buffer overflows vulnerabilities.
 Directory traversal attacks.

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Portability Testing
Portability testing includes the testing of Software with intend that it should be re-useable and can be
moved from another Software as well. Following are the strategies that can be used for Portability
testing.
 Transferred installed Software from one computer to another.
 Building executable (.exe) to run the Software on different platforms.
Portability testing can be considered as one of the sub parts of System testing, as this testing type
includes the overall testing of Software with respect to its usage over different environments.
Computer Hardware, Operating Systems and Browsers are the major focus of Portability testing.
Following are some pre-conditions for Portability testing:
 Software should be designed and coded, keeping in mind Portability Requirements.
 Unit testing has been performed on the associated components.
 Integration testing has been performed.
 Test environment has been established.
Testing documentation involves the documentation of artifacts which should be developed before or
during the testing of Software.
Documentation for Software testing helps in estimating the testing effort required, test coverage,
requirement tracking/tracing etc. This section includes the description of some commonly used
documented artifacts related to Software testing such as:
 Test Plan
 Test Scenario
 Test Case
 Traceability Matrix
Test Plan
A test plan outlines the strategy that will be used to test an application, the resources that will be
used, the test environment in which testing will be performed, the limitations of the testing and the
schedule of testing activities. Typically the Quality Assurance Team Lead will be responsible for
writing a Test Plan.
A test plan will include the following.
 Introduction to the Test Plan document
 Assumptions when testing the application

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 List of test cases included in Testing the application
 List of features to be tested
 What sort of Approach to use when testing the software
 List of Deliverables that need to be tested
 The resources allocated for testing the application
 Any Risks involved during the testing process
 A Schedule of tasks and milestones as testing is started
Test Scenario
A one line statement that tells what area in the application will be tested. Test Scenarios are used to
ensure that all process flows are tested from end to end. A particular area of an application can have
as little as one test scenario to a few hundred scenarios depending on the magnitude and complexity
of the application.
The term test scenario and test cases are used interchangeably however the main difference being
that test scenarios has several steps however test cases have a single step. When viewed from this
perspective test scenarios are test cases, but they include several test cases and the sequence that
they should be executed. Apart from this, each test is dependent on the output from the previous
test.
Test Case
Test cases involve the set of steps, conditions and inputs which can be used while performing the
testing tasks. The main intent of this activity is to ensure whether the Software Passes or Fails in
terms of its functionality and other aspects. There are many types of test cases like: functional,
negative, error, logical test cases, physical test cases, UI test cases etc.

CSE 6th
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Furthermore test cases are written to keep track of testing coverage of Software. Generally, there is
no formal template which is used during the test case writing. However, following are the main
components which are always available and included in every test case:
 Test case ID.
 Product Module.
 Product version.
 Revision history.
 Purpose
 Assumptions
 Pre-Conditions.
 Steps.
 Expected Outcome.
 Actual Outcome.
 Post Conditions.
Many Test cases can be derived from a single test scenario. In addition to this, some time it
happened that multiple test cases are written for single Software which is collectively known as test
suites.
Traceability Matrix
Traceability Matrix (also known as Requirement Traceability Matrix - RTM) is a table which is used to
trace the requirements during the Software development life Cycle. It can be used for forward tracing
(i.e. from Requirements to Design or Coding) or backward (i.e. from Coding to Requirements). There
are many user defined templates for RTM.
Each requirement in the RTM document is linked with its associated test case, so that testing can be
done as per the mentioned requirements. Furthermore, Bug ID is also include and linked with its
associated requirements and test case. The main goals for this matrix are:
 Make sure Software is developed as per the mentioned requirements.
 Helps in finding the root cause of any bug.
 Helps in tracing the developed documents during different phases of SDLC.

Software testing

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