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The test cases people contributed for Haskell […] are a bit strange

The test cases in Haskell simply generate a list of random words.

I created simple test cases.

import org.junit.Assert;
import org.junit.Test;

public class TestCaffeineBuzz {
@Test
public void testOutputJava() {
Assert.assertEquals("Java", CaffeineBuzz.caffeineBuzz(3));
}

@Test
public void testOutputJavaScript() {
	Assert.assertEquals("JavaScript", CaffeineBuzz.caffeineBuzz(6));
}

@Test
public void testOutputCoffeeScript() {
	Assert.assertEquals("CoffeeScript", CaffeineBuzz.caffeineBuzz(12));
}

@Test
public void testOutputMochaMissing() {
	Assert.assertEquals("mocha_missing!", CaffeineBuzz.caffeineBuzz(1));
}

}

The test cases people contributed for Haskell, and particularly Java are a bit strange. The original kata is string in, string out. I think following that model might help you with the Java test cases.