refactor: move all tests to a single file

Author: ashokdey

src/_DataStructures_/Trees/BinarySearchTree/bst-insertion.test.js

@@ -0,0 +1,170 @@
+const BinarySearchTree = require('./index');
+
+describe('Data Structure : Binary Search Tree', () => {
+  let bst;
+  let rootsLeftChild;
+  let rootsRightChild;
+  let rootsLeftChildsLeftChild;
+  let rootsLeftChildsRightChild;
+  let rootsRightChildsLeftChild;
+  let rootsRightChildsRightChild;
+
+  it('Binary Search Tree should be a Class', () => {
+    expect(typeof BinarySearchTree.prototype.constructor).toEqual('function');
+  });
+
+  describe('Creation of BST', () => {
+    it('Should create a BST with root 100', () => {
+      bst = new BinarySearchTree(100);
+      expect(bst.root.value).toEqual(100);
+    });
+
+    it('Should add element 20 to the left of root node', () => {
+      bst.add(20);
+      rootsLeftChild = bst.root.leftChild;
+      expect(rootsLeftChild.value).toEqual(20);
+    });
+
+    it('Should add element 500 to the right of root node', () => {
+      bst.add(500);
+      rootsRightChild = bst.root.rightChild;
+      expect(rootsRightChild.value).toEqual(500);
+    });
+
+    it('Should add element 10 to the left of root"s left child', () => {
+      bst.add(10);
+      rootsLeftChildsLeftChild = bst.root.leftChild.leftChild;
+      expect(rootsLeftChildsLeftChild.value).toEqual(10);
+    });
+
+    it('Should add element 30 to the right of root"s left child', () => {
+      bst.add(30);
+      rootsLeftChildsRightChild = bst.root.leftChild.rightChild;
+      expect(rootsLeftChildsRightChild.value).toEqual(30);
+    });
+
+    it("Should add element 400 to the left of root's right child", () => {
+      bst.add(400);
+      rootsRightChildsLeftChild = bst.root.rightChild.leftChild;
+      expect(rootsRightChildsLeftChild.value).toEqual(400);
+    });
+
+    it("Should add element 600 to the right of root's right child", () => {
+      bst.add(600);
+      rootsRightChildsRightChild = bst.root.rightChild.rightChild;
+      expect(rootsRightChildsRightChild.value).toEqual(600);
+    });
+  });
+
+  describe('Check insertion was as expected', () => {
+    it('Inorder traversal of the created bst should be [ 10, 20, 30, 100, 400, 500, 600 ]', () => {
+      expect(bst.inorder()).toEqual([10, 20, 30, 100, 400, 500, 600]);
+    });
+
+    it('Preorder traversal of the created bst should be [ 100, 20, 10, 30, 500, 400, 600 ]', () => {
+      expect(bst.preorder()).toEqual([100, 20, 10, 30, 500, 400, 600]);
+    });
+
+    it('Postorder traversal of the created bst should be [ 10, 30, 20, 400, 600, 500, 100 ]', () => {
+      expect(bst.postorder()).toEqual([10, 30, 20, 400, 600, 500, 100]);
+    });
+  });
+
+  describe('Check if BST `Is Empty`', () => {
+    bst = new BinarySearchTree(6);
+    const keys = [4, 9, 2, 5, 8, 12];
+    keys.forEach(el => bst.add(el));
+    it('Should return `false` when BST is not empty', () => {
+      expect(bst.isEmpty()).toEqual(false);
+    });
+
+    it('Should return `true` when BST is empty', () => {
+      keys.push(6);
+      keys.forEach(el => bst.remove(el));
+      expect(bst.isEmpty()).toEqual(true);
+    });
+  });
+
+  describe('Find maximum value in BST', () => {
+    bst = new BinarySearchTree(6);
+    [4, 9, 2, 5, 8, 12].forEach(el => bst.add(el));
+
+    it('Should expect maximum key', () => {
+      expect(bst.getMaximum()).toEqual(12);
+    });
+
+    it('Should expect new maximum key added in BST', () => {
+      bst.add(20);
+      expect(bst.getMaximum()).toEqual(20);
+    });
+  });
+
+  describe('Find the minimum value in BST', () => {
+    bst = new BinarySearchTree(6);
+    [4, 9, 2, 5, 8, 12].forEach(el => bst.add(el));
+
+    it('Should expect minimum key', () => {
+      expect(bst.getMinimum()).toEqual(2);
+    });
+
+    it('Should expect new minimum key added to BST', () => {
+      bst.add(1);
+      expect(bst.getMinimum()).toEqual(1);
+    });
+  });
+
+  describe('Remove Node in BST', () => {
+    bst = null;
+
+    beforeEach(() => {
+      bst = new BinarySearchTree(5);
+    });
+
+    it('Should delete() an element from Binary Search Tree', () => {
+      bst.add(4);
+      bst.add(9);
+      bst.add(2);
+      bst.delete(bst.root, 4);
+      expect(bst.inorder()).toEqual([2, 5, 9]);
+      bst.delete(bst.root, 2);
+      expect(bst.inorder()).toEqual([5, 9]);
+    });
+
+    it('Should return NULL if root is empty', () => {
+      const bst2 = new BinarySearchTree(6);
+      bst2.remove(6);
+      bst2.remove(9);
+      expect(bst2.root).toEqual(null);
+    });
+  });
+
+  describe('Search value in BST', () => {
+    bst = new BinarySearchTree(6);
+    [4, 9, 2, 5, 8, 12].forEach(el => bst.add(el));
+
+    it('Should return `true` for 8', () => {
+      expect(bst.searchFor(8)).toEqual(true);
+    });
+
+    it('Should return `false` for 100', () => {
+      expect(bst.searchFor(100)).toEqual(false);
+    });
+  });
+
+  describe('Traversals in BST', () => {
+    it('Should return the `Preorder Traversal` for given BST', () => {
+      const preOrderTraversal = bst.preorder();
+      expect(preOrderTraversal).toEqual([6, 4, 2, 5, 9, 8, 12]);
+    });
+
+    it('Should return the `Inorder Traversal` for given BST', () => {
+      const inOrderTraversal = bst.inorder();
+      expect(inOrderTraversal).toEqual([2, 4, 5, 6, 8, 9, 12]);
+    });
+
+    it('Should return the `Postorder Traversal` for given BST', () => {
+      const postOrderTraversal = bst.postorder();
+      expect(postOrderTraversal).toEqual([2, 5, 4, 8, 12, 9, 6]);
+    });
+  });
+});