Guava spike

Spike.java

import com.google.common.base.Predicate;
import com.google.common.collect.Collections2;
import com.google.common.collect.Lists;
import org.junit.Test;

import javax.annotation.Nullable;
import java.util.ArrayList;
import java.util.Collection;

import static org.fest.assertions.Assertions.assertThat;

/**
 * @author Eirik Meland <eirik.meland@conduct.no>
 */
public class Spike {

    private final Predicate<Integer> even = new Predicate<Integer>() {
        @Override
        public boolean apply(@Nullable Integer input) {
            if (input == null) {
                return false;
            } else {
                return input % 2 == 0;
            }
        }
    };

    @Test
    public void name() {
        // arrange
        ArrayList<Integer> integers = Lists.newArrayList(1, 2, 3, 4);

        // act
        Collection<Integer> evenIntegers = Collections2.filter(integers, even);

        // assert
        assertThat(evenIntegers).containsOnly(2, 4);
        assertThat(evenIntegers).excludes(6);

        integers.add(6);
        assertThat(evenIntegers).contains(6);
    }
}