How to run JUnit tests with Gradle?

Question

How do I add a junit 4 dependency correctly?

Assuming you’re resolving against a standard Maven (or equivalent) repo:

dependencies {
    ...
    testCompile "junit:junit:4.11"  // Or whatever version
}

Run those tests in the folders of tests/model?

You define your test source set the same way:

sourceSets {
    ...

    test {
        java {
            srcDirs = ["test/model"]  // Note @Peter's comment below
        }
    }
}

Then invoke the tests as:

./gradlew test

EDIT: If you are using JUnit 5 instead, there are more steps to complete, you should follow this tutorial.