BreadthFirstSearchTest.java

packagecom.thealgorithms.searches;

importstaticorg.junit.jupiter.api.Assertions.assertArrayEquals;
importstaticorg.junit.jupiter.api.Assertions.assertEquals;
importstaticorg.junit.jupiter.api.Assertions.assertTrue;

importcom.thealgorithms.datastructures.Node;
importjava.util.List;
importjava.util.Optional;
importorg.junit.jupiter.api.BeforeEach;
importorg.junit.jupiter.api.Test;

publicclassBreadthFirstSearchTest {
privateNode<String> root;
privateBreadthFirstSearch<String> bfs;

// Tree structure:
//
// A
// / | \
// B C D
// / \
// E F

@BeforeEach
publicvoidsetUp() {
// nodes declaration
root = newNode<>("A");

varnodeB = newNode<>("B");
varnodeC = newNode<>("C");
varnodeD = newNode<>("D");

varnodeE = newNode<>("E");
varnodeF = newNode<>("F");

// tree initialization
root.addChild(nodeB);
root.addChild(nodeC);
root.addChild(nodeD);

nodeB.addChild(nodeE);
nodeB.addChild(nodeF);

// create an instance to monitor the visited nodes
bfs = newBreadthFirstSearch<>();
 }

@Test
publicvoidtestSearchRoot() {
StringexpectedValue = "A";
List<String> expectedPath = List.of("A");

// check value
Optional<Node<String>> value = bfs.search(root, expectedValue);
assertEquals(expectedValue, value.orElseGet(() -> newNode<>("")).getValue());

// check path
assertArrayEquals(expectedPath.toArray(), bfs.getVisited().toArray());
 }

@Test
publicvoidtestSearchF() {
StringexpectedValue = "F";
List<String> expectedPath = List.of("A", "B", "C", "D", "E", "F");

// check value
Optional<Node<String>> value = Optional.of(bfs.search(root, expectedValue).orElseGet(() -> newNode<>(null)));
assertEquals(expectedValue, value.get().getValue());

// check path
assertArrayEquals(expectedPath.toArray(), bfs.getVisited().toArray());
 }

@Test
voidtestSearchNull() {
List<String> expectedPath = List.of("A", "B", "C", "D", "E", "F");
Optional<Node<String>> node = bfs.search(root, null);

// check value
assertTrue(node.isEmpty());

// check path
assertArrayEquals(expectedPath.toArray(), bfs.getVisited().toArray());
 }

@Test
voidtestNullRoot() {
varvalue = bfs.search(null, "B");
assertTrue(value.isEmpty());
 }

@Test
voidtestSearchValueThatNotExists() {
List<String> expectedPath = List.of("A", "B", "C", "D", "E", "F");
varvalue = bfs.search(root, "Z");

// check that the value is empty because it's not exists in the tree
assertTrue(value.isEmpty());

// check path is the whole list
assertArrayEquals(expectedPath.toArray(), bfs.getVisited().toArray());
 }
}