JUnit Testing for Java Developers

JUnit Testing for Java Developers

Duration: 3 Days

Description

This focused course provides Java developers with comprehensive training in unit testing using JUnit 5, the industry-standard testing framework. Participants learn to write effective test cases, organize test suites, and apply test-driven development practices using assertions and assumptions. The course emphasizes practical techniques for testing methods, exceptions, collections, and time-dependent code, while exploring advanced features such as parameterized tests, test lifecycle management, and mocking with Mockito.

Audience

This course is designed for Java developers who want to improve code quality and reliability through systematic testing practices. It’s ideal for software engineers working in agile environments, developers preparing for continuous integration workflows, and teams adopting test-driven development. Prior experience with Java programming is required.

Objectives

  • Write effective unit tests using JUnit 5 annotations and assertions
  • Organize and structure test classes and test suites for maintainability
  • Apply test-driven development (TDD) principles to guide software design
  • Use parameterized tests to verify behavior across multiple input scenarios
  • Test exceptions, edge cases, and boundary conditions systematically
  • Integrate mocking frameworks to isolate units of code for testing
  • Configure test lifecycle methods to manage setup and teardown operations
  • Measure and improve code coverage using testing metrics

Prerequisites

Participants must have solid Java programming experience, including proficiency with classes, methods, control structures, and basic object-oriented principles. Completion of an introductory or intermediate Java course is strongly recommended. Familiarity with an IDE such as IntelliJ IDEA or Eclipse is expected.

Course Outline

Module 1: Java 21 Overview

  • Java 21 as a Long-Term Support Release
  • Evolution from Java 17 to Java 21
  • Major Themes – Concurrency and Pattern Matching
  • Feature Status – Final, Preview, and Incubator

Module 2: JUnit 5 Fundamentals

  • JUnit 5 Architecture
  • Writing Your First Test
  • Annotations – @Test, @BeforeEach, @AfterEach
  • Assertions and Assertion Messages

Module 3: Advanced Assertions and Assumptions

  • Common Assertions
  • Asserting Collections and Arrays
  • Testing Exceptions with assertThrows
  • Assumptions for Conditional Test Execution

Module 4: Test Organization and Lifecycle

  • Test Class Structure
  • Lifecycle Annotations — @BeforeAll, @AfterAll
  • Nested Tests with @Nested
  • Disabling Tests and Conditional Execution

Module 5: Parameterized and Dynamic Tests

  • Parameterized Tests with @ParameterizedTest
  • Value Sources and CSV Sources
  • Method Sources and Custom Argument Providers
  • Dynamic Tests with @TestFactory

Module 6: Mocking and Test Doubles

  • Introduction to Test Doubles
  • Mocking with Mockito
  • Stubbing Method Behavior
  • Verifying Interactions

Module 7: Best Practices and Code Coverage

  • Writing Maintainable Tests
  • Testing Private Methods and Static Methods
  • Code Coverage Metrics
  • Continuous Integration and Automated Testing