java-tutorials/guava-modules/guava-collections-set/src/test/java/com/baeldung/guava/GuavaMapFromSetUnitTest.java

package com.baeldung.guava;

import com.google.common.base.Function;
import org.junit.Test;

import java.util.Arrays;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;

import static org.junit.Assert.assertTrue;

public class GuavaMapFromSetUnitTest {

    @Test
    public void givenStringSet_whenMapsToElementLength_thenCorrect() {
        Function<Integer, String> function = new Function<Integer, String>() {
            @Override
            public String apply(Integer from) {
                return Integer.toBinaryString(from);
            }
        };
        Set<Integer> set = new TreeSet<>(Arrays.asList(32, 64, 128));
        Map<Integer, String> map = new GuavaMapFromSet<Integer, String>(set, function);
        assertTrue(map.get(32).equals("100000")
                && map.get(64).equals("1000000")
                && map.get(128).equals("10000000"));
    }

    @Test
    public void givenIntSet_whenMapsToElementBinaryValue_thenCorrect() {
        Function<String, Integer> function = new Function<String, Integer>() {

            @Override
            public Integer apply(String from) {
                return from.length();
            }
        };
        Set<String> set = new TreeSet<>(Arrays.asList(
                "four", "three", "twelve"));
        Map<String, Integer> map = new GuavaMapFromSet<String, Integer>(set,
                function);
        assertTrue(map.get("four") == 4 && map.get("three") == 5
                && map.get("twelve") == 6);
    }

    @Test
    public void givenSet_whenNewSetElementAddedAndMappedLive_thenCorrect() {
        Function<String, Integer> function = new Function<String, Integer>() {

            @Override
            public Integer apply(String from) {
                return from.length();
            }
        };
        Set<String> set = new TreeSet<>(Arrays.asList(
                "four", "three", "twelve"));
        Map<String, Integer> map = new GuavaMapFromSet<String, Integer>(set,
                function);
        set.add("one");
        assertTrue(map.get("one") == 3 && map.size() == 4);
    }
}