Testing Fundamentals
Testing Fundamentals
Testing Fundamentals
Introduction
Testing is the process of evaluating a system or its component(s) with the intent to find whether it satisfies
the specified requirements or not.
Testing is executing a system in order to identify any gaps, errors, or missing requirements in contrary to the
actual requirements.
Before proceeding with this, you should have a basic understanding of the software development life cycle
(SDLC). In addition, you should have a basic understanding of software programming using any programming
language.
The testing is done by and depends on the process and the associated stakeholders of the project(s).
In the IT industry, large companies have a team with responsibilities to evaluate the developed software in
context of the given requirements. Moreover, developers also conduct testing which is called Unit Testing.
In most cases, the following professionals are involved in testing a system within their respective capacities:
Software Tester
Software Developer
Project Lead/Manager
End User
Different companies have different designations for people who test the software on the basis
of their experience and knowledge such as Software Tester, Software Quality Assurance
Engineer, QA Analyst, etc.
It is not possible to test the software at any time during its cycle.
An early start to testing reduces the cost and time to rework and produce error-free software
that is delivered to the client.
In Software Development Life Cycle (SDLC), testing can be started from the Requirements
Gathering phase and continued till the deployment of the software.
The following aspects are to be considered for stopping the testing process:
Testing Deadlines
Completion of test case execution
Completion of functional and code coverage to a certain point
Bug rate falls below a certain level and no high-priority bugs are identified
Management decision
Many organizations develop and implement different standards to improve the quality needs
of their software.
ISO/IEC 9126
This standard deals to determine the quality of a software application:
Quality model
External metrics
Internal metrics
This standard presents some set of quality attributes for any software such as:
Functionality
Reliability
Usability
Efficiency
Maintainability
Portability
ISO/IEC 9241-11
Part 11 of this standard deals with the extent to which a product can be used by specified users
to achieve specified goals with Effectiveness, Efficiency and Satisfaction in a specified
context of use.
This standard proposed a framework that describes the usability components and the
relationship between them. In this standard, the usability is considered in terms of user
performance and satisfaction. According to ISO 9241-11, usability depends on context of use
and the level of usability will change as the context changes.
ISO/IEC 25000:2005
ISO/IEC 25000:2005 is commonly known as the standard that provides the guidelines for
Software Quality Requirements and Evaluation (SQuaRE). This standard helps in organizing
and enhancing the process related to software quality requirements and their evaluations. In
reality, ISO-25000 replaces the two old ISO standards, i.e. ISO-9126 and ISO-14598.
General guide
ISO/IEC 12119
This standard deals with software packages delivered to the client. It does not focus or
deal with the clients’ production process.
Instructions for testing a delivered software package against the specified requirements.
The other standards related to QA and Testing processes are mentioned below:
Standard Description
IEEE 829 A standard for the format of documents used in different stages of software
testing.
IEEE 12207 A standard for software life cycle processes and life cycle data.
The different types of testing that may be used to test a software during SDLC.
Manual Testing
Manual testing includes testing a 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 tests the software to
identify any unexpected behavior or bug. There are different stages for manual testing such as
unit testing, integration testing, system testing, and user acceptance testing.
Testers use test plans, test cases, or test scenarios to test a 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 product. 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,
improves accuracy, and saves time and money in comparison to manual testing.
It is not possible to automate everything in a software. The areas at which a user can
make transactions such as the login form or registration forms, any area where large
number of users can access the software simultaneously should be automated.
Furthermore, all GUI items, connections with databases, field validations, etc. can be
efficiently tested by automating the manual process.
Accessing the application for load and performance with many virtual users
Availability of time
Execution of scripts
Selenium
SilkTest
TestComplete
Testing Anywhere
WinRunner
LoadRunner
WATIR
There are different methods that can be used for software testing.
Black-Box Testing
The technique of testing without having any knowledge of the interior workings of the application is called
black-box testing.
The tester is oblivious to the system architecture and does not have access to the source code. Typically, while
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.
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, a tester
needs to know the internal workings 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.
Grey-Box Testing
Grey-box testing is a technique to test the application with having a limited knowledge
of the internal workings of an application. In software testing, the phrase the more you know, the better carries
a lot of weight while 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, a tester can
prepare better test data and test scenarios while making a test plan.
Levels of testing include different methodologies that can be used while conducting software testing. The
main levels of software testing are:
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 a 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 while testing an application for functionality.
Steps Description
III The output based on the test data and the specifications of the application.
V The comparison of actual and expected results based on the executed test cases.
Unit Testing
This type of testing is performed by 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 different 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.
There is a limit to the number of scenarios and test data that a developer can use to verify a source code. After
having exhausted all the options, there is no choice but to stop unit testing and merge the code segment with
other units.
Integration Testing
Integration testing is defined as the testing of combined parts of an application to determine if they function
correctly. Integration testing can be done in two ways: Bottom-up integration testing and Top-down
integration testing.
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
In this testing, the highest-level modules are tested first and progressively, lower-level
modules are tested thereafter.
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 actual situations.
System Testing
System testing 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 the specified Quality Standards. This type of testing is performed by a
specialized testing team.
System testing is 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 that 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
application architecture.
Regression Testing
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. Regression testing is performed to verify that a fixed bug hasn't resulted
in another functionality or business rule violation. The intent of regression testing is to ensure that a change,
such as a bug fix should not result in another fault being uncovered in the application.
Minimize the gaps in testing when an application with changes made has to be tested.
Testing the new changes to verify that the changes made did not affect any other area of the application.
Acceptance Testing
This is the most important 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 requirement. 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 crashes or major errors in the application.
By performing acceptance tests on an application, the testing team will reduce 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 together is known as alpha testing. During this
phase, the following aspects 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.
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.
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 it to the general public will increase
customer satisfaction.
Non-Functional Testing
This is based upon testing an application from its non-functional attributes. Non-
functional testing involves testing a software from the requirements which are
nonfunctional in nature but important such as performance, security, user interface,
etc.
Some of the important and commonly used non-functional testing types are discussed
below.
Performance Testing
It is mostly used to identify any bottlenecks or performance issues rather than finding
bugs in a software. There are different causes that contribute in lowering the
performance of a software:
Network delay
Client-side processing
Performance testing is considered as one of the important and mandatory testing type
in terms of the following aspects:
Capacity
Stability
Scalability
Performance testing can be either qualitative or quantitative and can be divided into
different sub-types such as Load testing and Stress testing.
Load Testing
It is a process of testing the behavior of a 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 number of users can be
increased or decreased concurrently or incrementally based upon the requirements.
Stress Testing
Stress testing includes testing the behavior of a software under abnormal conditions.
For example, it may include taking away some resources or applying a load beyond the
actual load limit.
The aim of stress testing 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:
In addition to the different definitions of usability, there are some standards and quality models and methods
that define usability in the form of attributes and sub-attributes such as ISO-9126, ISO-9241-11, ISO-13407,
and IEEE std.610.12.
UI vs Usability Testing
UI testing involves testing the Graphical User Interface of the Software. UI testing ensures that the GUI
functions according to the requirements and tested in terms of color, alignment, size, and other properties.
On the other hand, usability testing ensures a good and user-friendly GUI that can be easily handled. UI testing
can be considered as a sub-part of usability testing.
Security Testing
Security testing involves testing a software in order to identify any flaws and gaps from
security and vulnerability point of view. Listed below are the main aspects that security
testing should ensure:
Confidentiality
Integrity
Authentication
Availability
Authorization
Non-repudiation
Injection flaws
Portability testing can be considered as one of the sub-parts of system testing, as this testing type includes
overall testing of a software with respect to its usage over different environments. Computer hardware,
operating systems, and browsers are the major focus of portability testing. Some of the pre-conditions for
portability testing are as follows:
Software should be designed and coded, keeping in mind the portability requirements.
Documentation for software testing helps in estimating the testing effort required, test
coverage, requirement tracking/tracing, etc.
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, and 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 includes the following:
Test Scenario
It is a one line statement that notifies 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 terms 'test scenario' and 'test cases' are used interchangeably, however a test scenario has several steps,
whereas a test case has a single step. 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 a set of steps, conditions, and inputs that can be used while performing testing tasks. The
main intent of this activity is to ensure whether a software passes or fails in terms of its functionality and other
aspects. There are many types of test cases such as functional, negative, error, logical test cases, physical test
cases, UI test cases, etc.
Furthermore, test cases are written to keep track of the testing coverage of a software. Generally, there are no
formal templates that can be used during test case writing. However, the following components 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, sometimes multiple test cases are
written for a single software which are collectively known as test suites.
Traceability Matrix
Traceability Matrix (also known as Requirement Traceability Matrix - RTM) is a table that 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 included and linked with its associated
requirements and test case. The main goals for this matrix are:
Test automation has specific advantages for improving the long-term efficiency of a software
team’s testing processes.
if the application’s user interface will change considerably in the near future, then any
If an application has a very tight deadline, there is currently no test automation available,
and it’s the testing get done within that time frame,