feat: add tests for binary search trees (#1769)

Data-Structures/Tree/test/BinarySearchTree.test.js

@@ -0,0 +1,66 @@
+import { Tree } from '../BinarySearchTree.js'
+
+describe('Binary Search Tree', () => {
+  let tree
+
+  beforeEach(() => {
+    tree = new Tree()
+    tree.addValue(10)
+    tree.addValue(5)
+    tree.addValue(15)
+    tree.addValue(3)
+    tree.addValue(8)
+  })
+
+  test('should add values to the tree', () => {
+    tree.addValue(12)
+
+    expect(tree.search(12)).toBe(12)
+    expect(tree.search(5)).toBe(5)
+    expect(tree.search(15)).toBe(15)
+  })
+
+  test('should perform in-order traversal', () => {
+    const values = []
+    const output = (val) => values.push(val)
+    tree.traverse(output)
+    expect(values).toEqual([3, 5, 8, 10, 15])
+  })
+
+  test('should remove leaf nodes correctly', () => {
+    tree.removeValue(5)
+    expect(tree.search(5)).toBeNull()
+  })
+
+  test('should remove nodes with one child correctly', () => {
+    tree.addValue(12)
+    tree.removeValue(15)
+
+    expect(tree.search(15)).toBeNull()
+    expect(tree.search(12)).toBe(12)
+  })
+
+  test('should remove nodes with two children correctly', () => {
+    tree.addValue(18)
+    tree.removeValue(15)
+
+    expect(tree.search(15)).toBeNull()
+    expect(tree.search(18)).toBe(18)
+  })
+
+  test('should return null for non-existent values', () => {
+    expect(tree.search(20)).toBeNull()
+    expect(tree.search(0)).toBeNull()
+  })
+
+  test('should handle removal of root node correctly', () => {
+    tree.removeValue(10)
+    expect(tree.search(10)).toBeNull()
+  })
+
+  test('should handle empty tree gracefully', () => {
+    const newTree = new Tree()
+    newTree.removeValue(22) // Should not throw
+    expect(newTree.search(22)).toBeNull()
+  })
+})