Understanding the Differences Between junit-jupiter-api and junit-jupiter-engine in Maven

What are the differences between the Maven modules junit-jupiter-api and junit-jupiter-engine, and do I need to include both in my build.gradle?

testCompile("org.junit.jupiter:junit-jupiter-engine:${junitVersion}")
testCompile("org.junit.jupiter:junit-jupiter-api:${junitVersion}")

JUnit 5 (JUnit Jupiter) comprises several components, two of the most important being junit-jupiter-api and junit-jupiter-engine. Understanding their roles and the necessity of including them in your project can enhance your testing capabilities.

dependencies {
    testCompile("org.junit.jupiter:junit-jupiter-api:${junitVersion}")
    testCompile("org.junit.jupiter:junit-jupiter-engine:${junitVersion}")
}

Causes

• JUnit is modular, with different artifact responsibilities.
• JUnit Jupiter API contains annotations and interfaces for writing tests.
• JUnit Jupiter Engine is responsible for executing the tests written using the API.

Solutions

• Include both dependencies in your build.gradle file for optimal functionality:
• `testCompile("org.junit.jupiter:junit-jupiter-api:${junitVersion}")`
• `testCompile("org.junit.jupiter:junit-jupiter-engine:${junitVersion}")`
• If only the engine is included, you will not have access to the test annotations and structures needed to define tests.

Mistake: Only including junit-jupiter-engine but not junit-jupiter-api.

Solution: You need both dependencies for proper testing. Always include junit-jupiter-api if you are writing tests.

Mistake: Neglecting to include versioning for dependencies.

Solution: Always specify the version of the dependencies you're including for consistency and avoid potential issues.