Master Spring Boot with Junit5: From basics to Advanced

Explore JUnit five, the modern Java testing framework, featuring the platform, Jupiter, and vintage modules, backward compatibility, extensions, parameterized tests, conditional tests, and dynamic testing.

Learn how to implement exception handling and negative testing in JUnit 5 by using assertThrows to verify thrown exceptions and inspect their messages.

Explore the JUnit Jupiter assertions API, mastering equals, null checks, true/false, and exception validation, plus array assertions, assert all, and line match.

Explore stubbing with Mockito to define mock behavior using when and thenReturn, argument matchers, and doThrow or doNothing while handling spies and partial mocks.

Set up a gradle spring boot project via start.spring.io with java 17, spring boot 3.1.5, jar packaging, and dependencies web, h2, spring data jpa; build and run on port 8080.

Learn to set up a Maven-based Spring Boot project with JDK 17 and dependencies Spring web, H2 database, and Spring Data JPA; import in IntelliJ, run, and verify with tests.

Create a Spring Boot application using start.spring.io with Gradle, Java 17, and dependencies Spring Web, Spring Data JPA, and H2.

Create a book service interface and implement it as a service layer, providing methods to get by title, get all, add, update, and delete books, with a not-found exception.

Create a Spring Boot REST controller for books with get by title, get all, add, update, and delete endpoints, backed by a book service and Swagger API docs.

Learn to debug in testing by setting breakpoints, inspecting variables, and stepping through code to identify, isolate, and fix issues in a Java application.

Develop and run unit tests for the book service layer using JUnit and Mockito, implementing setup with mocks, stubbing find by title, and asserting title and id.

Write a unit test for the getAllBooks method that returns a list of Book objects, stub findAll, and assert not null, list size, and title.

Develop and verify void methods in Spring Boot tests by using Mockito verify to confirm add book method calls the bookstore.save method, and explore do answer with argument inspection.

Learn to test void methods such as delete book using Mockito do nothing, verify, and argument capture to capture and validate input.

Develop negative tests for the update book method by mocking find by title and save, and asserting a book not found exception and message.

Demonstrates handling of a not-found scenario by testing delete by title with a not found exception, using junit5 assertions to verify exception type and message.

Explore the book controller in a spring boot app, using RestController and a book service to expose get, post, put, and delete mappings for single and all books, with tests.

Learn to write a controller layer test for a get book by title endpoint using Spring Boot test annotations, MockMvc, and MockBean, with given, when, and expect structure.

Enhance api testing by converting response data to a book object with an object mapper, then assert the title matches the expected value using MockMvc and json path.

Learn how to debug a http endpoint test using a print method that reveals request and response details, diagnose a 404 vs 200 mismatch, and fix the endpoint path.

Explain how to implement a delete mapping to remove a book by title via a path variable and test it with a delete request that returns http 200 ok.

Explore how controller advice, a specialization of the component annotation, enables global exception handling across all controller methods with @ExceptionHandler, @InitBinder, and @ModelAttribute, using ResponseEntityExceptionHandler for centralized error responses.

Modify the get book method to add a try-catch and book not found exception, returning bad request on exceptions and ok when a book is found, enabling negative controller tests.

Demonstrate a negative test case for a controller method by stubbing get book by title to throw an exception and asserting a bad request response.

Globalize exception handling with a controller advice for the book controller, returning a custom exception message in a response entity for bad requests when a book is not found.

Learn to test the JPA data layer in Spring Boot using @DataJpaTest, which configures JPA components and uses an in-memory H2 database for unit tests with automatic rollback.

explore h2 in-memory database for spring boot unit testing, an embedded open-source relational dbms with jdbc api, and learn to configure via pom.xml and spring.h2.console.enabled.

Learn the database integration test flow from book controller to book service to S2 DB by implementing add book and get book by title tests.

Master integration testing for a book app by building a Spring Boot test with auto configured MockMvc, an H2 database, and JSON-driven post requests to save and retrieve books.

Explore an integration testing flow that retrieves all books from an external library server via the books controller API and the book service, without a database.

Set up an external server integration test to fetch books, inject the library server URL from application properties (localhost:7070), and run Spring Boot test with MockMvc and active int profiles.