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| 1 | +const BinarySearchTree = require('./index'); |
| 2 | + |
| 3 | +describe('Data Structure : Binary Search Tree', () => { |
| 4 | + let bst; |
| 5 | + let rootsLeftChild; |
| 6 | + let rootsRightChild; |
| 7 | + let rootsLeftChildsLeftChild; |
| 8 | + let rootsLeftChildsRightChild; |
| 9 | + let rootsRightChildsLeftChild; |
| 10 | + let rootsRightChildsRightChild; |
| 11 | + |
| 12 | + it('Binary Search Tree should be a Class', () => { |
| 13 | + expect(typeof BinarySearchTree.prototype.constructor).toEqual('function'); |
| 14 | + }); |
| 15 | + |
| 16 | + describe('Creation of BST', () => { |
| 17 | + it('Should create a BST with root 100', () => { |
| 18 | + bst = new BinarySearchTree(100); |
| 19 | + expect(bst.root.value).toEqual(100); |
| 20 | + }); |
| 21 | + |
| 22 | + it('Should add element 20 to the left of root node', () => { |
| 23 | + bst.add(20); |
| 24 | + rootsLeftChild = bst.root.leftChild; |
| 25 | + expect(rootsLeftChild.value).toEqual(20); |
| 26 | + }); |
| 27 | + |
| 28 | + it('Should add element 500 to the right of root node', () => { |
| 29 | + bst.add(500); |
| 30 | + rootsRightChild = bst.root.rightChild; |
| 31 | + expect(rootsRightChild.value).toEqual(500); |
| 32 | + }); |
| 33 | + |
| 34 | + it('Should add element 10 to the left of root"s left child', () => { |
| 35 | + bst.add(10); |
| 36 | + rootsLeftChildsLeftChild = bst.root.leftChild.leftChild; |
| 37 | + expect(rootsLeftChildsLeftChild.value).toEqual(10); |
| 38 | + }); |
| 39 | + |
| 40 | + it('Should add element 30 to the right of root"s left child', () => { |
| 41 | + bst.add(30); |
| 42 | + rootsLeftChildsRightChild = bst.root.leftChild.rightChild; |
| 43 | + expect(rootsLeftChildsRightChild.value).toEqual(30); |
| 44 | + }); |
| 45 | + |
| 46 | + it("Should add element 400 to the left of root's right child", () => { |
| 47 | + bst.add(400); |
| 48 | + rootsRightChildsLeftChild = bst.root.rightChild.leftChild; |
| 49 | + expect(rootsRightChildsLeftChild.value).toEqual(400); |
| 50 | + }); |
| 51 | + |
| 52 | + it("Should add element 600 to the right of root's right child", () => { |
| 53 | + bst.add(600); |
| 54 | + rootsRightChildsRightChild = bst.root.rightChild.rightChild; |
| 55 | + expect(rootsRightChildsRightChild.value).toEqual(600); |
| 56 | + }); |
| 57 | + }); |
| 58 | + |
| 59 | + describe('Check insertion was as expected', () => { |
| 60 | + it('Inorder traversal of the created bst should be [ 10, 20, 30, 100, 400, 500, 600 ]', () => { |
| 61 | + expect(bst.inorder()).toEqual([10, 20, 30, 100, 400, 500, 600]); |
| 62 | + }); |
| 63 | + |
| 64 | + it('Preorder traversal of the created bst should be [ 100, 20, 10, 30, 500, 400, 600 ]', () => { |
| 65 | + expect(bst.preorder()).toEqual([100, 20, 10, 30, 500, 400, 600]); |
| 66 | + }); |
| 67 | + |
| 68 | + it('Postorder traversal of the created bst should be [ 10, 30, 20, 400, 600, 500, 100 ]', () => { |
| 69 | + expect(bst.postorder()).toEqual([10, 30, 20, 400, 600, 500, 100]); |
| 70 | + }); |
| 71 | + }); |
| 72 | + |
| 73 | + describe('Check if BST `Is Empty`', () => { |
| 74 | + bst = new BinarySearchTree(6); |
| 75 | + const keys = [4, 9, 2, 5, 8, 12]; |
| 76 | + keys.forEach(el => bst.add(el)); |
| 77 | + it('Should return `false` when BST is not empty', () => { |
| 78 | + expect(bst.isEmpty()).toEqual(false); |
| 79 | + }); |
| 80 | + |
| 81 | + it('Should return `true` when BST is empty', () => { |
| 82 | + keys.push(6); |
| 83 | + keys.forEach(el => bst.remove(el)); |
| 84 | + expect(bst.isEmpty()).toEqual(true); |
| 85 | + }); |
| 86 | + }); |
| 87 | + |
| 88 | + describe('Find maximum value in BST', () => { |
| 89 | + bst = new BinarySearchTree(6); |
| 90 | + [4, 9, 2, 5, 8, 12].forEach(el => bst.add(el)); |
| 91 | + |
| 92 | + it('Should expect maximum key', () => { |
| 93 | + expect(bst.getMaximum()).toEqual(12); |
| 94 | + }); |
| 95 | + |
| 96 | + it('Should expect new maximum key added in BST', () => { |
| 97 | + bst.add(20); |
| 98 | + expect(bst.getMaximum()).toEqual(20); |
| 99 | + }); |
| 100 | + }); |
| 101 | + |
| 102 | + describe('Find the minimum value in BST', () => { |
| 103 | + bst = new BinarySearchTree(6); |
| 104 | + [4, 9, 2, 5, 8, 12].forEach(el => bst.add(el)); |
| 105 | + |
| 106 | + it('Should expect minimum key', () => { |
| 107 | + expect(bst.getMinimum()).toEqual(2); |
| 108 | + }); |
| 109 | + |
| 110 | + it('Should expect new minimum key added to BST', () => { |
| 111 | + bst.add(1); |
| 112 | + expect(bst.getMinimum()).toEqual(1); |
| 113 | + }); |
| 114 | + }); |
| 115 | + |
| 116 | + describe('Remove Node in BST', () => { |
| 117 | + bst = null; |
| 118 | + |
| 119 | + beforeEach(() => { |
| 120 | + bst = new BinarySearchTree(5); |
| 121 | + }); |
| 122 | + |
| 123 | + it('Should delete() an element from Binary Search Tree', () => { |
| 124 | + bst.add(4); |
| 125 | + bst.add(9); |
| 126 | + bst.add(2); |
| 127 | + bst.delete(bst.root, 4); |
| 128 | + expect(bst.inorder()).toEqual([2, 5, 9]); |
| 129 | + bst.delete(bst.root, 2); |
| 130 | + expect(bst.inorder()).toEqual([5, 9]); |
| 131 | + }); |
| 132 | + |
| 133 | + it('Should return NULL if root is empty', () => { |
| 134 | + const bst2 = new BinarySearchTree(6); |
| 135 | + bst2.remove(6); |
| 136 | + bst2.remove(9); |
| 137 | + expect(bst2.root).toEqual(null); |
| 138 | + }); |
| 139 | + }); |
| 140 | + |
| 141 | + describe('Search value in BST', () => { |
| 142 | + bst = new BinarySearchTree(6); |
| 143 | + [4, 9, 2, 5, 8, 12].forEach(el => bst.add(el)); |
| 144 | + |
| 145 | + it('Should return `true` for 8', () => { |
| 146 | + expect(bst.searchFor(8)).toEqual(true); |
| 147 | + }); |
| 148 | + |
| 149 | + it('Should return `false` for 100', () => { |
| 150 | + expect(bst.searchFor(100)).toEqual(false); |
| 151 | + }); |
| 152 | + }); |
| 153 | + |
| 154 | + describe('Traversals in BST', () => { |
| 155 | + it('Should return the `Preorder Traversal` for given BST', () => { |
| 156 | + const preOrderTraversal = bst.preorder(); |
| 157 | + expect(preOrderTraversal).toEqual([6, 4, 2, 5, 9, 8, 12]); |
| 158 | + }); |
| 159 | + |
| 160 | + it('Should return the `Inorder Traversal` for given BST', () => { |
| 161 | + const inOrderTraversal = bst.inorder(); |
| 162 | + expect(inOrderTraversal).toEqual([2, 4, 5, 6, 8, 9, 12]); |
| 163 | + }); |
| 164 | + |
| 165 | + it('Should return the `Postorder Traversal` for given BST', () => { |
| 166 | + const postOrderTraversal = bst.postorder(); |
| 167 | + expect(postOrderTraversal).toEqual([2, 5, 4, 8, 12, 9, 6]); |
| 168 | + }); |
| 169 | + }); |
| 170 | +}); |
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