Unit testing is a type of software testing where individual units or components of a software are tested to determine if they are fit for use. It is done during development by developers to test standalone modules. There are three phases of unit testing: arrange, act, and assert (AAA). Unit testing has advantages like easier debugging and quick fixes but also disadvantages like more test code needing to be written. Unit test implementation involves writing test cases, setting up fixtures, executing tests, and ensuring code quality.

1. Software
Testing
Software Project - VI
Afnanul Hassan
Adjunct Lecturer
Department of CSE
Daffodil International University

2. WHAT
Software testing is defined as an activity to check
whether the actual results match the expected results
and to ensure that the software system is Defect free.
WHY
• In April 2015, Bloomberg terminal in London crashed due to software glitch affected more than
300,000 traders on financial markets. It forced the government to postpone a 3bn pound debt
sale.
• Nissan cars recalled over 1 million cars from the market due to software failure in the airbag
sensory detectors. There has been reported two accident due to this software failure.
• Starbucks was forced to close about 60 percent of stores in the U.S and Canada due to software
failure in its POS system. At one point, the store served coffee for free as they were unable to
process the transaction.
• Vulnerability in Windows 10. This bug enables users to escape from security sandboxes through
a flaw in the win32k system.
• In 1985, Canada’s Therac-25 radiation therapy machine malfunctioned due to software bug and
delivered lethal radiation doses to patients, leaving 3 people dead and critically injuring 3 others.
• In April of 1999, a software bug caused the failure of a $1.2 billion military satellite launch, the
costliest accident in history
• In May of 1996, a software bug caused the bank accounts of 823 customers of a major U.S. bank
to be credited with 920 million US dollars.
Software
Testing

3. TYPES
Functional Testing
• Unit Testing
• Integration Testing
• System Testing
• UAT ( User Acceptance Testing)
• Localization
• Globalization
• Interoperability
• So on
Non-Functional Testing
• Performance
• Endurance
• Load
• Volume
• Scalability
• Usability
• So on….
Software
Testing
Top 20 Software Testing Services (QA Companies) in 2022

4. Unit
Testing

5. WHAT
Unit testing is a software development process in which the
smallest testable parts of an application, called units, are
individually and independently scrutinized for proper operation.
MORE
• It is also called Component Testing.
• It performed on standalone module to check if it is working or not.
• Units are meant to be independent and individually functional.
• Units are also known as SUT (System Under Test)
• This testing methodology is done during the development.
• Developers can do this type of testing.
Unit
Testing
PHASES
Three unit test phases are also known as
• Arrange,
• Act and
• Assert (Always outputs Boolean)
or simply AAA.

6. Disadvantage
• Tests will not uncover every bug.
• Unit tests only test sets of data and its functionality—it will not catch errors in integration.
• More lines of test code may need to be written to test one line of code—creating a potential
time investment.
• Unit testing may have a steep learning curves, for example, having to learn how to use specific
automated Software Tools.
Unit
Testing Advantage
• The earlier a problem is identified, the fewer compound errors occur.
• Costs of fixing a problem early can quickly outweigh the cost of fixing it later.
• Debugging processes are made easier.
• Developers can quickly make changes to the code base.
• Developers can also re-use code, migrating it to new projects.

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25. Thank
You