package com.insightfullogic.java8.exercises.chapter5;
import org.junit.Test;
import java.util.List;
import java.util.Map;
import java.util.stream.Stream;
import static java.util.Arrays.asList;
import static org.junit.Assert.assertEquals;
public class GroupingByTest {
@Test
public void stringsByLength() {
GroupingBy<String, Integer> stringIntegerGroupingBy = new GroupingBy<>(String::length);
Map<Integer,List<String>> results = Stream.of("a", "b", "cc", "dd")
.collect(stringIntegerGroupingBy);
System.out.println(results);
assertEquals(2, results.size());
assertEquals(asList("a", "b"), results.get(1));
assertEquals(asList("cc", "dd"), results.get(2));
}
}