Internship note

CI Tools

1. JaCoCo (Java Code Coverage)

Purpose: Code coverage analysis tool

• Measures how much of your source code is exercised by your unit tests

• Tracks:

  • Line coverage
  • Branch coverage
  • Method/class coverage

• Generates visual HTML reports showing what parts of code are untested

Typical Use Cases:

• Works with JUnit and Mockito
• Integrated into CI pipelines (Jenkins, GitHub Actions, etc.)

Example (Maven):

mvn clean test jacoco:report

Report Path (Maven): target/site/jacoco/index.html

2. PMD (Programming Mistake Detector)

Purpose: Static code analysis

• Scans your Java code for potential issues like:

  • Poor naming conventions
  • Dead code
  • Empty catch blocks
  • Duplicate or overly complex code

• Helps enforce coding standards and best practices

• Can be customized with your own rule sets

Similar tools: Checkstyle, SpotBugs

Example (Maven):

mvn pmd:pmd

Report Path: target/site/pmd.html

3. Mockito

Purpose: Mocking framework for unit testing

• Used to simulate dependencies during tests
• Lets you mock methods, define return values, and verify interactions
• Prevents your tests from calling real external systems (DBs, APIs, etc.)

Example:

MyService mockService = Mockito.mock(MyService.class);
when(mockService.fetchData()).thenReturn("Mock Result");

assertEquals("Mock Result", mockService.fetchData());
verify(mockService).fetchData();

Often used with JUnit

🔄 Summary Comparison

Tool	What it does	Typical Use
JaCoCo	Measures test coverage	After unit testing
PMD	Static analysis for code quality	During development/code review
Mockito	Mocks dependencies in tests	Inside unit tests