import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;

import java.util.Arrays;
import java.util.Collection;

public class SimpleTest {

    private static FileMerge fileMerge;

    @BeforeAll
    public static void init() {
        fileMerge = new GreedyFileMerge();
    }

    @Test
    public void test1() {
        Collection<File> files = Arrays.asList(
                new TestFile(300),
                new TestFile(7000),
                new TestFile(20000)
        );

        TestFile.cost = 0;
        File file = fileMerge.merge(files);

        Assertions.assertEquals(27300, file.size(), "Niet alle bestanden zijn gemerged.");
        Assertions.assertEquals(34600, TestFile.cost, "De kost van het mergen is niet optimaal.");
    }

    @Test
    public void test2() {
        Collection<File> files = Arrays.asList(
                new TestFile(20),
                new TestFile(30),
                new TestFile(10),
                new TestFile(5),
                new TestFile(30)
        );

        TestFile.cost = 0;
        File file = fileMerge.merge(files);

        Assertions.assertEquals(95, file.size(), "Niet alle bestanden zijn gemerged.");
        Assertions.assertEquals(205, TestFile.cost, "De kost van het mergen is niet optimaal.");
    }

    static class TestFile implements File {
        static private int cost = 0;
        private long size;

        TestFile(long size) {
            this.size = size;
        }

        @Override
        public long size() {
            return size;
        }

        @Override
        public File merge(File other) {
            cost += size + other.size();
            return new TestFile(size + other.size());
        }
    }

}