Junit 5 From Basics To Advanced

Unit Testing in Java

What you'll learn

Unit Testing

JUnit5

Mockito

Java Testing Framework

Requirements

Java

Description

Unit testing roadmap:Topics already covered:- Available Frameworks:- Junit- TestNG etc.- What is a unit test?- Difference between unit vs integration vs functional tests- AAA (Arrange-Act-Assert)- Maven/Gradle dependencies- Test Lifecycle- Basic Annotations:     • @Test     • @BeforeEach, @AfterEach     • @BeforeAll, @AfterAll     • @DisplayName     • @Disableetc.- Assertions:     • assertEquals, assertNotEquals     • assertTrue, assertFalse     • assertNull, assertNotNull     • assertThrows for exception testing- Extensions- Test Repetition    • @RepeatedTest(n)Upcoming:- Parameterized TestsMocking- Available Frameworks:     - Mockito     - EasyMock     - JMock- Mockito Core Concepts:     • @Mock and Mockito.mock(Class.class)     • @InjectMocks for injecting mocks     • @BeforeEach with MockitoAnnotations.openMocks(this)     • Testing Private/Static Methods (PowerMock or some other approach)- Stubbing Behavior     • when(…).thenReturn(…)     • when(…).thenThrow(…)- Verifying Calls     • verify(…) after method call     • verifyNoMoreInteractions(…)- Void Method Stubbing     • doNothing().when(mock).method()     • doThrow(…).when(…)- Argument Matchers:     • any(), eq(), anyString(), anyInt(), etc.     • Mixing matchers with exact values (and why it fails)- Behavior Verification:- Verify how many times called: times(n), never(), atLeastOnce()- Spies vs Mocks:     ○ Mockito.spy() for partial mocking     ○ Difference between mock() and spy()- Testing Configuration, Properties, and Profiles- Unit tests with different Spring profiles.- How to mock @Value, Environment, or @ConfigurationProperties.- Overriding properties for test-only behavior. Assertions & Matchers    - Frameworks:     - AssertJ     - HamcrestSome Advanced Topics- Test-Driven Development (TDD)- Write failing test first, then code- Test Coverage:     • Tools: JaCoCo, IntelliJ coverage tool- CI integration- Run tests in GitHub Actions, GitLab CI/CD, Jenkins.- Test Reports- Generate HTML/XML test reports for build tools.AI + Unit Testing- Code Suggestion Tools (AI-Powered IDE Extensions)- Using AI in CI/CD (Future-Forward)- AI suggests missing test cases for changed methods- AI flags flaky or redundant tests- Autogenerate Missing Tests

Overview

Section 1: JUnit 5

Lecture 1 JUnit 5: Unit Testing Introduction | Unit vs Integration vs Functional Testing

Lecture 2 JUnit 5 Architecture : JUnit Platform, JUnit Jupiter and JUnit Vintage

Lecture 3 JUnit 5 Tests Lifecycle, Parallel Execution and AAA pattern

Lecture 4 JUnit 5 Assertions

Lecture 5 JUnit 5 : Extensions in depth

Lecture 6 JUnit 5: RepeatedTest in depth

Java Backend Developers