JUnit & Unit Testing

What is JUnit?

• JUnit is a free and open-source unit testing framework.
• It is specifically designed for Java applications.
• Initially released in 1997.
• It has become one of the most popular testing frameworks in the Java community.

Features of JUnit

• Lightweight and easy to use.
• Allows Java developers to write unit test cases.
• Current version: 5.8.0.

Architecture of JUnit

• JUnit has three main modules:
  • JUnit Platform
  • JUnit Jupiter
  • JUnit Vintage
• JUnit Platform provides support for running tests.
• JUnit Jupiter offers new annotations and features.
• JUnit Vintage provides backward compatibility for previous JUnit versions.

Purpose of Assertions

• Assertions are used to compare the expected output and the actual output of a test case.
• Different types of assertions like:
  • assertTrue
  • assertEquals
  • assertNull
  • assertNotNull

Mocking

• Mocking is used for isolated unit testing.
• It is the process of creating substitutes (mock objects) for real objects.
• Two types of mock frameworks:
  • Stub-based mock frameworks
  • Bytecode manipulation-based mock frameworks

Unit Testing Process

• The unit testing process involves testing individual pieces of code.
• Developers are responsible for performing unit testing of their application.

Spring Boot and REST API

• Spring Boot is used to develop REST APIs.
• REST (Representational State Transfer) is an architectural style for web services.
• REST APIs are used in distributed applications.

Code Coverage

• Code coverage is a metric that indicates how much code is tested.
• JaCoCo is a tool used to generate code coverage reports.
• Code coverage reports show which lines are tested and which are not.

Conclusion

• Unit testing and code coverage are important.
• It is necessary to cover all important lines during unit testing.
• JaCoCo is used to measure code coverage.
• It ensures that the developed code meets quality standards.

Practice and Next Steps

• All necessary examples will be provided for students to practice.
• A new workshop will be held next week.
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