Merge pull request #4644 from bi-/master

Delete the root element from the tree.

data-structures/src/main/java/com/baeldung/tree/BinaryTree.java

@@ -57,7 +57,7 @@ public class BinaryTree {
     }
 
     public void delete(int value) {
-        deleteRecursive(root, value);
+        root = deleteRecursive(root, value);
     }
 
     private Node deleteRecursive(Node current, int value) {

data-structures/src/test/java/com/baeldung/tree/BinaryTreeUnitTest.java

@@ -6,7 +6,7 @@ import static org.junit.Assert.assertTrue;
 
 import org.junit.Test;
 
-public class BinaryTreeTest {
+public class BinaryTreeUnitTest {
 
     @Test
     public void givenABinaryTree_WhenAddingElements_ThenTreeNotEmpty() {
@@ -70,6 +70,17 @@ public class BinaryTreeTest {
         assertEquals(initialSize, bt.getSize());
     }
 
+    @Test
+    public void it_deletes_the_root() {
+        int value = 12;
+        BinaryTree bt = new BinaryTree();
+        bt.add(value);
+
+        assertTrue(bt.containsNode(value));
+        bt.delete(value);
+        assertFalse(bt.containsNode(value));
+    }
+
     @Test
     public void givenABinaryTree_WhenTraversingInOrder_ThenPrintValues() {
 

data-structures/src/test/java/com/baeldung/trie/TrieUnitTest.java

@@ -6,7 +6,7 @@ import org.junit.jupiter.api.Assertions;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
-public class TrieTest {
+public class TrieUnitTest {
 
     @Test
     public void whenEmptyTrie_thenNoElements() {