TDD Lab — Design Your Own Object

In this lab you will design and build your own Java class from scratch and write tests for it using everything you learned in class — including JUnit 5 and JaCoCo for coverage reporting.

Your goal is to hit 80% code coverage driven entirely by your tests.

An example is provided in the object.example package — see Person.java and PersonTest.java for reference.

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How To Get Started

Step 1 — Fork This Repo

Click the Fork button in the top right corner of this page.

Step 2 — Clone Your Fork

Clone the repo to your local machine and open the project in IntelliJ.

Step 3 — Create Your Package

Inside src/main/java/object/ create a new package using your first and last name — all lowercase, no dashes:

src/main/java/object/firstnamelastname/

For example:

src/main/java/object/jordaneldridge/

Do the same inside src/test/java/object/:

src/test/java/object/firstnamelastname/

Step 4 — Create Your Class and Test File

Inside your package create your class file and your test file:

src/main/java/object/firstnamelastname/YourClassName.java
src/test/java/object/firstnamelastname/YourClassNameTest.java

Step 5 — Do Not Touch the Example Package

Do not modify anything inside object.example — this is the reference example only.

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Running Your Tests

From the root of the project run:

mvn clean test

You should see output that ends with:

BUILD SUCCESS

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Viewing Your Coverage Report

After running mvn clean test open your JaCoCo report:

open target/site/jacoco/index.html

Click into your class name to see a method level breakdown. Your goal is 80% or above. Any method showing 0% is a gap — write a test for it.

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Lab Requirements

Your class must have:

• At least 5 fields
• A constructor that takes all fields as parameters
• Getters and setters for all fields
• At least 2 custom methods beyond getters and setters
• At least one validation using IllegalArgumentException

Your tests must cover:

• Constructor happy path and validation
• All getters and setters
• All custom methods including happy path, edge cases, and validation
• At least one assertThrows
• AAA pattern visible in every test

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How To Submit

Step 1 — Commit and Push Your Work

Step 2 — Open a Pull Request

In the PR description include:

• What object you chose and why
• Your JaCoCo coverage percentage
• Anything you found challenging or interesting

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Important Rules

• Only add files inside your own package — never modify anyone else's package
• Do not modify the object.example package

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Grading Checklist

• At least 5 fields with getters and setters
• At least 2 custom methods with meaningful behavior
• Tests for constructor, getters, setters, and all custom methods
• At least one validation test using assertThrows
• JaCoCo coverage at 80% or above
• Correct package name — all lowercase, no dashes
• Pull Request open with correct title and description