This interview question is to check if you know the basic rules about writing a JUnit test method:

* You need to mark the method as a JUnit test method with the JUnit annotation: @org.junit.Test.

* A JUnit test method must be a "public" method. This allows the runner class to access this method.

* A JUnit test method must be a "void" method. The runner class does not check any return values.

* A JUnit test should perform one JUnit assertion - calling an org.junit.Assert.assertXXX() method.

Here is a simple JUnit test method:

import org.junit.*;

...

@Test public void testHello() {

String message = "Hello World!";

Assert.assertEquals(12, message.length());

}