diff --git a/core-java-8/src/test/java/com/baeldung/list/AddElementsUnitTest.java b/core-java-8/src/test/java/com/baeldung/list/AddElementsUnitTest.java new file mode 100644 index 0000000000..93c28812bd --- /dev/null +++ b/core-java-8/src/test/java/com/baeldung/list/AddElementsUnitTest.java @@ -0,0 +1,87 @@ +package com.baeldung.list; + +import org.junit.Assert; +import org.junit.Before; +import org.junit.Test; + +import java.util.*; + +import static org.junit.Assert.*; + +public class AddElementsUnitTest { + + List flowers; + + @Before + public void init() { + this.flowers = new ArrayList<>(Arrays.asList( + new Flower("Poppy", 12), + new Flower("Anemone", 8), + new Flower("Catmint", 12))); + } + + @Test + public void givenAList_whenTargetListIsEmpty_thenReturnTargetListWithNewItems() { + List anotherList = new ArrayList<>(); + anotherList.addAll(flowers); + + assertEquals(anotherList.size(), flowers.size()); + Assert.assertTrue(anotherList.containsAll(flowers)); + } + + @Test + public void givenAList_whenTargetListIsEmpty_thenReturnTargetListWithOneModifiedElementByConstructor() { + List anotherList = new ArrayList<>(); + anotherList.addAll(flowers); + + Flower flower = anotherList.get(0); + flower.setPetals(flowers.get(0).getPetals() * 3); + + assertEquals(anotherList.size(), flowers.size()); + Assert.assertTrue(anotherList.containsAll(flowers)); + } + + @Test + public void givenAListAndElements_whenUseCollectionsAddAll_thenAddElementsToTargetList() { + List target = new ArrayList<>(); + + Collections.addAll(target, flowers.get(0), flowers.get(1), flowers.get(2), flowers.get(0)); + + assertEquals(target.size(), 4); + } + + @Test + public void givenTwoList_whenSourceListDoesNotHaveNullElements_thenAddElementsToTargetListSkipFirstElementByStreamProcess() { + List flowerVase = new ArrayList<>(); + + flowers.stream() + .skip(1) + .forEachOrdered(flowerVase::add); + + assertEquals(flowerVase.size() + 1, flowers.size()); + assertFalse(flowerVase.containsAll(flowers)); + } + + @Test + public void givenTwoList_whenSourceListDoesNotHaveNullElements_thenAddElementsToTargetListFilteringElementsByStreamProcess() { + List flowerVase = new ArrayList<>(); + + flowers.stream() + .filter(f -> f.getPetals() > 10) + .forEachOrdered(flowerVase::add); + + assertEquals(flowerVase.size() + 1, flowers.size()); + assertFalse(flowerVase.containsAll(flowers)); + } + + @Test + public void givenAList_whenListIsNotNull_thenAddElementsToListByStreamProcessWihtOptional() { + List target = new ArrayList<>(); + + Optional.ofNullable(flowers) + .ifPresent(target::addAll); + + assertNotNull(target); + assertEquals(target.size(), 3); + } +}