AboutCollections.java

package itw;

import java.util.Collection;

public class AboutCollections {


    /**
     * La méthode retourne une liste avec les élements de stringList sans les doublons.
     *
     * @param stringList
     * @return
     */
    public Collection<String> uniqueElements(final Collection<String> stringList) {














    }

    /**
     * La méthode retourne une liste contenant les élements de toutes les listes passées en paramètre.
     *
     * @param lists
     * @return
     */
    public Collection<String> createOneBigCollection(Collection<String> l1, Collection<String> l2, Collection<String> l3) {














    }
}

AboutCollectionsTest.java

package itw;

import org.junit.Before;
import org.junit.Test;

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

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

public class AboutCollectionsTest {


    private AboutCollections obj;

    @Before
    public void setUp() {
        obj = new AboutCollections();
    }

    @Test
    public void testUniqueElements() {

        Collection<String> stringList = Arrays.asList("david", "alexandre", "nicolas", "beko", "alexandre", "nicolas");

        Collection<String> result = obj.uniqueElements(stringList);

        assertEquals(4, result.size());
        assertTrue(result.contains("david"));
        assertTrue(result.contains("alexandre"));
        assertTrue(result.contains("nicolas"));
        assertTrue(result.contains("beko"));
    }



    @Test
    public void testOneBigCollection() {

        Collection<String> stringList1 = Arrays.asList("mickey", "donald");
        Collection<String> stringList2 = Arrays.asList("pluto", "daisy");
        Collection<String> stringList3 = Arrays.asList("bugs bunny", "picsou");

        Collection<String> result = obj.createOneBigCollection(stringList1, stringList2, stringList3);

        assertEquals(6, result.size());
        assertTrue(result.contains("mickey"));
        assertTrue(result.contains("daisy"));
        assertTrue(result.contains("bugs bunny"));

    }
}