Gradle supports both Java and Groovy projects. When build Groovy project , the best test framework is Spock, when work with Java project, the test framework is JUnit. Even the Spock is actually compatible with JUnit, like Gradle compatible with Maven.

Step 1. Create directory structure

For a typical Java project, the directory layout would be like this

 
src\main
src\main\java\
src\test
src\test\java
 

Step 2. Create java class and test class

Add a java class under src\main\java\HelloWorld.java

 
 
class HelloWorld {
    public String Hello ( String str ) {
        System.out.println("Hello" + str );
        return str;
    } 
}
 

And the JUnit test class

 
 
import org.junit.Test;
import static org.junit.Assert.*;
 
public class RunTest {
  @Test
  public void RunTest() {
      HelloWorld h = new HelloWorld();
      String str = "World";
 
      assertEquals(str, h.Hello(str));
  }
}
 
 
 

Step 3. Gradle build file

The build file is simple

 
apply plugin: 'java'
 
repositories {
    mavenCentral()
}
 
dependencies {
    testCompile 'junit:junit:4.8.2'
}
 
 

The build process will execute all the tests in test directory. Run the build command

 
gradle build