java-tutorials/libraries-6/src/test/java/com/baeldung/protonpack/ProtonpackUnitTest.java

package com.baeldung.protonpack;

import com.codepoetics.protonpack.Indexed;
import com.codepoetics.protonpack.StreamUtils;
import com.codepoetics.protonpack.collectors.CollectorUtils;
import com.codepoetics.protonpack.collectors.NonUniqueValueException;
import com.codepoetics.protonpack.selectors.Selectors;
import org.junit.Test;

import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import static java.util.Arrays.asList;
import static java.util.Arrays.stream;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

public class ProtonpackUnitTest {
    @Test
    public void whenTakeWhile_thenTakenWhile() {
        Stream<Integer> streamOfInt = Stream.iterate(1, i -> i + 1);
        List<Integer> result = StreamUtils.takeWhile(streamOfInt, i -> i < 5).collect(Collectors.toList());
        assertThat(result).contains(1, 2, 3, 4);
    }

    @Test
    public void whenTakeUntil_thenTakenUntil() {
        Stream<Integer> streamOfInt = Stream.iterate(1, i -> i + 1);
        List<Integer> result = StreamUtils.takeUntil(streamOfInt, i -> i > 50).collect(Collectors.toList());
        assertThat(result).contains(10, 20, 30, 40);
    }

    @Test
    public void givenMultipleStream_whenZipped_thenZipped() {
        String[] clubs = {"Juventus", "Barcelona", "Liverpool", "PSG"};
        String[] players = {"Ronaldo", "Messi", "Salah"};
        Set<String> zippedFrom2Sources = StreamUtils
          .zip(stream(clubs), stream(players), (club, player) -> club + " " + player)
          .collect(Collectors.toSet());
        assertThat(zippedFrom2Sources).contains("Juventus Ronaldo", "Barcelona Messi", "Liverpool Salah");

        String[] leagues = {"Serie A", "La Liga", "Premier League"};
        Set<String> zippedFrom3Sources = StreamUtils.zip(stream(clubs), stream(players), stream(leagues),
          (club, player, league) -> club + " " + player + " " + league).collect(Collectors.toSet());
        assertThat(zippedFrom3Sources).contains("Juventus Ronaldo Serie A", "Barcelona Messi La Liga",
          "Liverpool Salah Premier League");
    }

    @Test
    public void whenZippedWithIndex_thenZippedWithIndex() {
        Stream<String> streamOfClubs = Stream.of("Juventus", "Barcelona", "Liverpool");
        Set<Indexed<String>> zipsWithIndex = StreamUtils.zipWithIndex(streamOfClubs).collect(Collectors.toSet());
        assertThat(zipsWithIndex).contains(Indexed.index(0, "Juventus"), Indexed.index(1, "Barcelona"),
          Indexed.index(2, "Liverpool"));
    }

    @Test
    public void givenMultipleStream_whenMerged_thenMerged() {
        Stream<String> streamOfClubs = Stream.of("Juventus", "Barcelona", "Liverpool", "PSG");
        Stream<String> streamOfPlayers = Stream.of("Ronaldo", "Messi", "Salah");
        Stream<String> streamOfLeagues = Stream.of("Serie A", "La Liga", "Premier League");

        Set<String> merged = StreamUtils.merge(() -> "", (valOne, valTwo) -> valOne + " " + valTwo, streamOfClubs,
          streamOfPlayers, streamOfLeagues).collect(Collectors.toSet());

        assertThat(merged)
          .contains(" Juventus Ronaldo Serie A", " Barcelona Messi La Liga", " Liverpool Salah Premier League",
            " PSG");
    }

    @Test
    public void givenMultipleStream_whenMergedToList_thenMergedToList() {
        Stream<String> streamOfClubs = Stream.of("Juventus", "Barcelona", "PSG");
        Stream<String> streamOfPlayers = Stream.of("Ronaldo", "Messi");

        List<List<String>> mergedListOfList = StreamUtils.mergeToList(streamOfClubs, streamOfPlayers)
          .collect(Collectors.toList());
        assertThat(mergedListOfList.get(0)).isInstanceOf(List.class);
        assertThat(mergedListOfList.get(0)).containsExactly("Juventus", "Ronaldo");
        assertThat(mergedListOfList.get(1)).containsExactly("Barcelona", "Messi");
        assertThat(mergedListOfList.get(2)).containsExactly("PSG");
    }

    @Test
    public void givenMultipleStream_whenInterleaved_thenInterleaved() {
        Stream<String> streamOfClubs = Stream.of("Juventus", "Barcelona", "Liverpool");
        Stream<String> streamOfPlayers = Stream.of("Ronaldo", "Messi");
        Stream<String> streamOfLeagues = Stream.of("Serie A", "La Liga");

        List<String> interleavedList = StreamUtils
          .interleave(Selectors.roundRobin(), streamOfClubs, streamOfPlayers, streamOfLeagues)
          .collect(Collectors.toList());

        assertThat(interleavedList)
          .hasSize(7)
          .containsExactly("Juventus", "Ronaldo", "Serie A", "Barcelona", "Messi", "La Liga", "Liverpool");
    }

    @Test
    public void whenSkippedUntil_thenSkippedUntil() {
        Integer[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
        List<Integer> skippedUntilGreaterThan5 = StreamUtils.skipUntil(stream(numbers), i -> i > 5)
          .collect(Collectors.toList());
        assertThat(skippedUntilGreaterThan5).containsExactly(6, 7, 8, 9, 10);

        List<Integer> skippedUntilLessThanEquals5 = StreamUtils.skipUntil(stream(numbers), i -> i <= 5)
          .collect(Collectors.toList());
        assertThat(skippedUntilLessThanEquals5).containsExactly(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
    }

    @Test
    public void whenSkippedWhile_thenSkippedWhile() {
        Integer[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
        List<Integer> skippedWhileLessThanEquals5 = StreamUtils.skipWhile(stream(numbers), i -> i <= 5)
          .collect(Collectors.toList());
        assertThat(skippedWhileLessThanEquals5).containsExactly(6, 7, 8, 9, 10);

        List<Integer> skippedWhileGreaterThan5 = StreamUtils.skipWhile(stream(numbers), i -> i > 5)
          .collect(Collectors.toList());
        assertThat(skippedWhileGreaterThan5).containsExactly(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
    }

    @Test
    public void givenFibonacciGenerator_whenUnfolded_thenUnfolded() {
        Stream<Integer> unfolded = StreamUtils.unfold(2, i -> (i < 100) ? Optional.of(i * i) : Optional.empty());

        assertThat(unfolded.collect(Collectors.toList())).containsExactly(2, 4, 16, 256);
    }

    @Test
    public void whenWindowed_thenWindowed() {
        Integer[] numbers = {1, 2, 3, 4, 5, 6, 7};

        List<List<Integer>> windowedWithSkip1 = StreamUtils.windowed(stream(numbers), 3, 1)
          .collect(Collectors.toList());
        assertThat(windowedWithSkip1)
          .containsExactly(asList(1, 2, 3), asList(2, 3, 4), asList(3, 4, 5), asList(4, 5, 6),
            asList(5, 6, 7));

        List<List<Integer>> windowedWithSkip2 = StreamUtils.windowed(stream(numbers), 3, 2)
          .collect(Collectors.toList());
        assertThat(windowedWithSkip2).containsExactly(asList(1, 2, 3), asList(3, 4, 5), asList(5, 6, 7));
    }

    @Test
    public void whenAggregated_thenAggregated() {
        Integer[] numbers = {1, 2, 2, 3, 4, 4, 4, 5};
        List<List<Integer>> aggregated = StreamUtils
          .aggregate(stream(numbers), (int1, int2) -> int1.compareTo(int2) == 0)
          .collect(Collectors.toList());
        assertThat(aggregated).containsExactly(asList(1), asList(2, 2), asList(3), asList(4, 4, 4), asList(5));

        List<List<Integer>> aggregatedFixSize = StreamUtils.aggregate(stream(numbers), 5).collect(Collectors.toList());
        assertThat(aggregatedFixSize).containsExactly(asList(1, 2, 2, 3, 4), asList(4, 4, 5));
    }

    @Test
    public void whenGroupedRun_thenGroupedRun() {
        Integer[] numbers = {1, 1, 2, 3, 4, 4, 5};
        List<List<Integer>> grouped = StreamUtils.groupRuns(stream(numbers)).collect(Collectors.toList());
        assertThat(grouped).containsExactly(asList(1, 1), asList(2), asList(3), asList(4, 4), asList(5));

        Integer[] numbers2 = {1, 2, 3, 1};
        List<List<Integer>> grouped2 = StreamUtils.groupRuns(stream(numbers2)).collect(Collectors.toList());
        assertThat(grouped2).containsExactly(asList(1), asList(2), asList(3), asList(1));
    }

    @Test
    public void whenAggregatedOnListCondition_thenAggregatedOnListCondition() {
        Integer[] numbers = {1, 1, 2, 3, 4, 4, 5};
        Stream<List<Integer>> aggregated = StreamUtils.aggregateOnListCondition(stream(numbers),
          (currentList, nextInt) -> currentList.stream().mapToInt(Integer::intValue).sum() + nextInt <= 5);
        assertThat(aggregated).containsExactly(asList(1, 1, 2), asList(3), asList(4), asList(4), asList(5));
    }

    @Test
    public void givenProjectionFunction_whenMaxedBy_thenMaxedBy() {
        Stream<String> clubs = Stream.of("Juventus", "Barcelona", "PSG");
        Optional<String> longestName = clubs.collect(CollectorUtils.maxBy(String::length));
        assertThat(longestName).contains("Barcelona");
    }

    @Test
    public void givenStreamOfMultipleElem_whenUniqueCollector_thenValueReturned() {
        Stream<Integer> singleElement = Stream.of(1);
        Optional<Integer> unique = singleElement.collect(CollectorUtils.unique());
        assertThat(unique).contains(1);
    }

    @Test
    public void givenStreamOfMultipleElem_whenUniqueCollector_thenExceptionThrown() {
        Stream<Integer> multipleElement = Stream.of(1, 2, 3);
        assertThatExceptionOfType(NonUniqueValueException.class).isThrownBy(() -> {
            multipleElement.collect(CollectorUtils.unique());
        });
    }
}