Software Testing - Unit 2 (Black Box Testing and Levels of Testing)

SOFTWARE TESTING
Presented By
M.SINDHU
Assistant Professor,
Kongu Engineering College,
Perundurai.
M.SINDHU,Assistant Professor, Kongu Engineering College.

UNIT-II
Black Box Testing
&
Levels of Testing

Black Box Testing
 Black box testing is a technique of software testing which
examines the functionality of software without peering
into its internal structure or coding. The primary source of
black box testing is a specification of requirements that is
stated by the customer.
 In this method, tester selects a function and gives input
value to examine its functionality, and checks whether
the function is giving expected output or not. If the
function produces correct output, then it is passed in
testing, otherwise failed. The test team reports the result
to the development team and then tests the next
function

Requirements-based testing
 Requirements-based testing is a testing approach in which
test cases, conditions and data are derived from
requirements. It includes functional tests and also non-
functional attributes such as performance, reliability or
usability.
Stages :
 Defining Test Completion Criteria
 Design Test Cases
 Execute Tests
 Verify Test Results
 Verify Test Coverage
 Track and Manage Defects

Requirements Testing process:
 Testing must be carried out in a timely
manner.
 Testing process should add value to the
software life cycle, hence it needs to be
effective.
 Testing the system exhaustively is impossible
hence the testing process needs to be
efficient as well.
 Testing must provide the overall status of
the project, hence it should be
manageable.

Requirement traceability Matrix -
Parameters:
Requirement ID
Risks
Requirement Type
Requirement Description
Trace to Design Specification
Unit Test Cases
Integration Test Cases
System Test Cases
User Acceptance Test Cases
Trace to Test Script

What is Positive Testing?
 It is used to check whether our application works as
expected or not. And if an error is detected at the time of
positive testing, the test is considered as fail. A positive
testing is a technique whenever a test engineer writes the
test cases for a set of respective outputs.
 In positive testing, the test engineer will always check for
only a good set of values.
 In other words, we can say that positive testing is a process
where the system or an application is tested against the
valid input data.
 And the primary purpose of performing the positive testing
is to validate whether the software does what it is
supposed to do.
 In simple terms, we can say that positive testing is
implemented by providing a positive point of view.

What is Negative Testing?
 It is implemented to check how the application can
gracefully handle invalid input or unpredicted user
performance.
 The fundamental purpose of executing the negative
testing is to ensure the application's stability against the
effects of different variations of improper validation
data set.
 Negative testing is also known as error path testing or
failure. And it helps us to identify more bugs and
enhance the quality of the software application under
test.
 Once the positive testing is complete, then only we can
execute the negative testing, which helps to identify
more bugs and enhance the quality of the software
application under test.

Boundary Value Analysis
 Boundary value analysis is one of the widely used case
design technique for black box testing. It is used to test
boundary values because the input values near the
boundary have higher chances of error.
 Whenever we do the testing by boundary value analysis,
the tester focuses on, while entering boundary value
whether the software is producing correct output or not.
 Boundary values are those that contain the upper and
lower limit of a variable. Assume that, age is a variable of
any function, and its minimum value is 18 and the
maximum value is 30, both 18 and 30 will be considered
as boundary values.
 The basic assumption of boundary value analysis is, the
test cases that are created using boundary values are
most likely to cause an error.

Example:
 Imagine, there is a function that accepts a number
between 18 to 30, where 18 is the minimum and 30 is
the maximum value of valid partition, the other values
of this partition are 19, 20, 21, 22, 23, 24, 25, 26, 27, 28
and 29. The invalid partition consists of the numbers
which are less than 18 such as 12, 14, 15, 16 and 17,
and more than 30 such as 31, 32, 34, 36 and 40. Tester
develops test cases for both valid and invalid partitions
to capture the behavior of the system on different
input conditions.

Decision Table
 Decision table technique is one of the widely used case
design techniques for black box testing. This is a systematic
approach where various input combinations and their
respective system behavior are captured in a tabular form.
 That's why it is also known as a cause-effect table. This
technique is used to pick the test cases in a systematic
manner; it saves the testing time and gives good coverage
to the testing area of the software application.
 Decision table technique is appropriate for the functions
that have a logical relationship between two and more
than two inputs.
 This technique is related to the correct combination of
inputs and determines the result of various combinations of
input. To design the test cases by decision table technique,
we need to consider conditions as input and actions as
output.

Example:
 Most of us use an email account, and when you want to
use an email account, for this you need to enter the email
and its associated password.
 If both email and password are correctly matched, the user
will be directed to the email account's homepage;
otherwise, it will come back to the login page with an error
message specified with "Incorrect Email" or "Incorrect
Password.“

Equivalence class partitioning
 Equivalence Partitioning Method is also known as
Equivalence class partitioning (ECP). It is a software testing
technique or black-box testing that divides input domain
into classes of data, and with the help of these classes of
data, test cases can be derived.
 An ideal test case identifies class of error that might
require many arbitrary test cases to be executed before
general error is observed.
 In equivalence partitioning, equivalence classes are
evaluated for given input conditions.
 Whenever any input is given, then type of input condition
is checked, then for this input conditions, Equivalence
class represents or describes set of valid or invalid states.

Guidelines for Equivalence Partitioning :
 If the range condition is given as
an input, then one valid and two
invalid equivalence classes are
defined.
 If a specific value is given as
input, then one valid and two
invalid equivalence classes are
defined.
 If a member of set is given as an
input, then one valid and one
invalid equivalence class is
defined.
 If Boolean no. is given as an input
condition, then one valid and
one invalid equivalence class is
defined.

Advantages and disadvantages of Equivalence Partitioning
technique

State Based Testing
 The general meaning of state transition is, different
forms of the same situation, and according to the
meaning, the state transition method does the same.
It is used to capture the behavior of the software
application when different input values are given to
the same function.
 There is a login function of an application which
provides a maximum three number of attempts, and
after exceeding three attempts, it will be directed to
an error page.

Compatibility Testing
 It is part of non-functional testing.
 Checking the functionality of an application on different
software, hardware platforms, network, and browsers is
known as compatibility testing.
Compatibility testing tools
 Some of the most commonly used compatibility testing
tools are as follows:
 LambdaTest
 BrowserStack
 BrowseEMAll
 TestingBot

Compatibility testing process
 Here, we are performing an O.S (Operating system) compatibility testing process.
 Firstly, the customer will give the functional requirement as well as a non-
functional requirement.
 After getting the non-functional requirement, the one base platform will decide
according to the most commonly used platform.
 After that, the test engineer will start functional testing on the base platform until
the application is functional stable.
 We have to test the application on a different platform, so for this, we have a
VMware software.
 For compatibility testing, we will use VM Server where we install all necessary
operating system and browser, and access that server using Remote Desktop
connection.
 We access VMware set up remotely, and after that, the test engineer will do one
round of compatibility testing on the platform and check the end-to-end flow.
 The end-to-end flow will go on until the application is stable, and applications
work fine for all necessary platforms and handover to the customer.
 Note2:For Browser compatibility testing, we don't have to go for the VMware
setup, since multiple browsers can be installed in a single machine as well as they
also are accessed simultaneously.
 In the case of various versions of the same browser, we have to go with VMware
set up since multiple versions of the browser cannot be accessed simultaneously
from a single system.
 We can do Software compatibility testing on different platforms.

Testing Documentation
 Testing documentation is the documentation of artifacts that
are created during or before the testing of a software
application.
 Documentation reflects the importance of processes for the
customer, individual and organization.
 Projects which contain all documents have a high level of
maturity. Careful documentation can save the time, efforts
and wealth of the organization.

Types of test document

Benefits of using Documentation
 Documentation clarifies the quality of methods and objectives.
 It ensures internal coordination when a customer uses software
application.
 It ensures clarity about the stability of tasks and performance.
 It provides feedback on preventive tasks.
 It provides feedback for your planning cycle.
 It creates objective evidence for the performance of the quality
management system.
 If we write the test document, we can't forget the values which we put in
the first phase.
 It is also a time-saving process because we can easily refer to the text
document.
 It is also consistent because we will test on the same value.
The drawback of the test document
 It is a bit tedious because we have to maintain the modification provided
by the customer and parallel change in the document.
 If the test documentation is not proper, it will replicate the quality of the
application.
 Sometimes it is written by that person who does not have the product
knowledge.
 Sometimes the cost of the document will be exceeding its value.

Domain testing
 Domain testing is a testing process where the software is tested
to ensure it doesn't accept invalid or out-of-range values.
 The output is tested against a minimum number of inputs to see
whether the system is accepting the input within the required
range or not. The white box testing is a perfect example of
domain testing.
Domain Testing Strategy
 A specific boundary defines every domain. During the test,
testers analyze each point nearby those boundaries. Each
testing process starts with a question, and the purpose of
domain testing is to find solutions to these questions.
 What domains to choose for the testing process?
 What values should one choose for the test?
 How do you group values into classes?
 How do you get the results?

Is it important to have domain knowledge for
domain testing?
 Is it important to have domain knowledge for domain testing?
 It is highly important to have at least basic domain knowledge for
an expert to conduct domain testing.
 Domain knowledge is crucial as each industry or field is unique and
has specific requirements.
 Retail − In retail domains, the workflow runs at different levels.
Therefore, testing engineers looking forward to running domain
testing in retail must know how things work in warehouse
management, in-store solutions, and so on.
 Online Banking − Online backing consists of several crucial internet-
dependent activities such as login, money transfer, bill payment,
etc., which is quite different than retails.
 Healthcare − Handling healthcare domains is quite critical as it holds
a huge risk to someone's life. Besides, it includes numerous menial
yet time-consuming tasks like patient's entry, health history,
prescriptions, setting & modifying schedules, insurance, etc.

Levels of Testing
 In software testing we
have four different
levels of testing, which
are as discussed below:
 Unit Testing
 Integration Testing
 System Testing
 Acceptance Testing

Level1: Unit Testing
 Unit testing is the first level of software testing, which is used
to test if software modules are satisfying the given
requirement or not.
 The first level of testing involves analyzing each unit or an
individual component of the software application.
 Unit testing is also the first level of functional testing. The
primary purpose of executing unit testing is to validate unit
components with their performance.
 A unit component is an individual function or regulation of
the application, or we can say that it is the smallest testable
part of the software. The reason of performing the unit
testing is to test the correctness of inaccessible code.
 Unit testing will help the test engineer and developers in
order to understand the base of code that makes them
able to change defect causing code quickly. The
developers implement the unit.

Level2: Integration Testing
 The second level of software testing is the integration testing. The
integration testing process comes after unit testing.
 It is mainly used to test the data flow from one module or
component to other modules.
 In integration testing, the test engineer tests the units or separate
components or modules of the software in a group.
 The primary purpose of executing the integration testing is to
identify the defects at the interaction between integrated
components or units.
 When each component or module works separately, we need to
check the data flow between the dependent modules, and this
process is known as integration testing.
 We only go for the integration testing when the functional testing
has been completed successfully on each application module.
 In simple words, we can say that integration testing aims to
evaluate the accuracy of communication among all the
modules.

Level3: System Testing
 The third level of software testing is system testing, which is
used to test the software's functional and non-functional
requirements.
 It is end-to-end testing where the testing environment is
parallel to the production environment. In the third level of
software testing, we will test the application as a whole
system.
 To check the end-to-end flow of an application or the
software as a user is known as System testing.
 In system testing, we will go through all the necessary
modules of an application and test if the end features or the
end business works fine, and test the product as a complete
system.
 In simple words, we can say that System testing is a
sequence of different types of tests to implement and
examine the entire working of an integrated software
computer system against requirements.

Level4: Acceptance Testing
 The last and fourth level of software testing is acceptance
testing, which is used to evaluate whether a specification or
the requirements are met as per its delivery.
 The software has passed through three testing levels (Unit
Testing, Integration Testing, System Testing). Some minor
errors can still be identified when the end-user uses the
system in the actual scenario.
 In simple words, we can say that Acceptance testing is
the squeezing of all the testing processes that are
previously done.
 The acceptance testing is also known as User acceptance
testing (UAT) and is done by the customer before
accepting the final product.
 Usually, UAT is done by the domain expert (customer) for
their satisfaction and checks whether the application is
working according to given business scenarios and real-
time scenarios.

Software Testing - Unit 2 (Black Box Testing and Levels of Testing)

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