JUnit and Mockito Crash Course

Kick off this JUnit and Mockito crash course by exploring its sectioned structure and startup setup, enjoy self-paced quizzes for self-check, then practice writing unit tests and asking questions.

Master unit testing by validating public methods with varied inputs, handling positive and exception scenarios, and using JUnit with Mockito to mock dependencies for fast, isolated tests.

Maven automates building, testing, packaging, and deployment of Java projects using convention over configuration, with a standard folder layout (src/main/java, src/main/resources, src/test/java, src/test/resources), archetypes, and IDE support.

Create a maven project in Eclipse, add JUnit 5 dependencies (JUnit Jupiter engine and Vintage engine) to pom.xml, set the compiler to 1.8, and migrate tests to JUnit 5.

Build a Maven project, run tests automatically, and generate a jar in the target directory. Run Maven install to compile sources, execute tests, and produce artifacts with sure fire reports.

Download and unzip the order processing service, import as a maven project in Eclipse, configure pom.xml dependencies for JUnit 5 and Mockito to test the bo and dao layers.

Learn how mocking enables unit testing by isolating a unit from its dependencies, using mock objects, stubbing, and verifying with Mockito. Follow the three steps: stubbing, setting expectations, and verifying.

Learn how test coverage measures which source lines are executed by unit tests, identify gaps, and use tools like JaCoCo, Cobertura, and EclEmma within CI pipelines.

Explore how Mockito matchers simplify stubbing and verification, using any int and other matchers to handle inputs without creating full objects.

Set up the Mockito scrapbook Maven project in Eclipse, import JUnit and Mockito dependencies, and prepare to test class A by mocking B’s void method.

Learn the F.I.R.S.T principle for agile software testing, ensuring fast, independent, repeatable, self-validating, and timely unit tests to deliver quick feedback across environments.

Explore partial mocking with a Mockito spy to reuse real methods while stubbing selective behavior, including using doReturn with a spy and contrasting with when, in a practical list example.

Understand spy versus mock in Mockito: spies use the real object unless stubbed, while mocks are library objects, and use when syntax to stub or call real methods when needed.

Download the Maven project, import it into Eclipse, install Tomcat 9, run the simple Java web app with a coupon servlet, two jsp pages, and JUnit/Mockito tests.

Create unit tests for a servlet by mocking http servlet request, response, and request dispatcher with Mockito, generating doGet and doPost tests and running them as JUnit tests.

Update existing tests to use parameterized values, mark the test class with the parameterized runner, and verify multiple data sets yield expected results, showcasing parameterized testing in JUnit.