intermediate

Test-Driven Development in Java, JUnit, and Mockito

Software Engineering

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Master TDD in Java using JUnit - write tests first, implement code, and refactor. Learn test doubles with the Mockito framework to isolate components. Create cleaner, more maintainable code while reducing bugs and improving development efficiency.

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465 learners

This course introduces Test-Driven Development (TDD) for Java projects, covering the Red-Green-Refactor workflow, TDD mindset, and setup with JUnit. Learn best practices like SOLID principles and dependency injection, and explore TDD's impact on code quality and speed compared to traditional approaches.

Course 2

Red-Green-Refactor: Practicing TDD with Java & JUnit

5 lessons

25 practices

This course focuses on practicing the core TDD workflow: "Red-Green-Refactor." You'll write failing tests (Red), implement code to pass them (Green), and refactor while keeping tests passing (Refactor). No new concepts are introduced—just hands-on practice with various requirements to sharpen your TDD skills.

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Course 3

Isolating Dependencies with Test Doubles using JUnit & Mockito

5 lessons

26 practices

Discover the pivotal role of test doubles in modern software testing. This introductory course will guide you through the essentials of dummies, stubs, spies, mocks, and fakes. Learn how these powerful tools help you isolate units under test, control behavior, and build reliable, fast, and maintainable tests. Step into the world of test doubles and elevate your software development skills.

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Course 4

Refactoring by Leveraging Tests with Java & JUnit

5 lessons

21 practices

This course focuses on the Refactor step in TDD, teaching developers to spot code smells and resolve them through refactoring. Using real-world examples, you'll identify common issues, apply refactoring techniques, and ensure functionality is preserved with existing tests.

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I'm impressed by the quality and can't stop recommending it. It's also a lot of fun!

Francisco Aguilar Meléndez

Data Scientist

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From our community

Hear what our customers have to say about CodeSignal Learn

I'm impressed by the quality and can't stop recommending it. It's also a lot of fun!

Francisco Aguilar Meléndez

Data Scientist

+11

I love that it's personalized. When I'm stuck, I don't have to hope my Google searches come out successful. The AI mentor Cosmo knows exactly what I need.

Faith Yim

Software Engineer

+14

It's an amazing product and exceeded my expectations, helping me prepare for my job interviews. Hands-on learning requires you to actually know what you are doing.

Alex Bush

Full Stack Engineer

I'm really impressed by the AI tutor Cosmo's feedback about my code. It's honestly kind of insane to me that it's so targeted and specific.

Abbey Helterbran

Tech consultant

I tried Leetcode but it was too disorganized. CodeSignal covers all the topics I'm interested in and is way more structured.

Jonathan Miller

Senior Machine Learning Engineer

+12

I'm impressed by the quality and can't stop recommending it. It's also a lot of fun!

Francisco Aguilar Meléndez

Data Scientist

+11

Test-Driven Development in Java, JUnit, and Mockito

Trusted by learners working at top companies

Turn screen time into skills time

Join the 1M+ learners on CodeSignal

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