test: write test cases for methods in array class

Author: francislagares

jest.config.js

@@ -0,0 +1,5 @@
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  roots: ['<rootDir>/src/'],
+};

package.json

@@ -9,7 +9,8 @@
   "scripts": {
     "build": "tsc --watch",
     "start": "nodemon dist/index.js",
-    "dev": "concurrently \"yarn:build\" \"yarn:start\""
+    "dev": "concurrently \"yarn:build\" \"yarn:start\"",
+    "test": "jest --watchAll --no-cache"
   },
   "husky": {
     "hooks": {

src/arrays/__tests__/arrays.test.ts

@@ -0,0 +1,46 @@
+import { myArray } from '../arrayClass';
+
+describe('Array Class Implementation', () => {
+  test('new empty array is created', () => {
+    const array = new myArray();
+    expect(array.isEmpty()).toBe(true);
+  });
+
+  test('create new array with 5 elements', () => {
+    const array = new myArray(1, 2, 3, 4, 5);
+    expect(array.size()).toEqual(5);
+  });
+
+  test('get value from a given index in array', () => {
+    const array = new myArray(
+      { id: 1, name: 'Francis' },
+      { id: 2, name: 'Carole' }
+    );
+    expect(array.get(1)).toEqual({ id: 2, name: 'Carole' });
+  });
+
+  test('push value to end of array', () => {
+    const array = new myArray();
+    expect(array.push('Hello')).toBe(1);
+    expect(array.push('there')).toBe(2);
+  });
+
+  test('remove last item in array', () => {
+    const array = new myArray(
+      ['name', 'Francis'],
+      ['name', 'Erika'],
+      ['name', 'Peter']
+    );
+    expect(array.pop()).toEqual(['name', 'Peter']);
+  });
+
+  test('delete item at a given index of array', () => {
+    const array = new myArray(
+      { id: 1, name: 'Francis' },
+      { id: 2, name: 'Carole' },
+      { id: 3, name: 'Peter' },
+      { id: 4, name: 'Erika' }
+    );
+    expect(array.delete(2)).toEqual({ id: 3, name: 'Peter' });
+  });
+});

src/arrays/arrayClass.ts

@@ -1,8 +1,8 @@
-class myArray<T> {
+export class myArray<T> {
   private length: number;
   private data: {};
 
-  public constructor(args?: T[]) {
+  public constructor(...args: T[]) {
     this.length = args.length;
     this.data = {};
     for (const key in args) {
@@ -18,7 +18,7 @@ class myArray<T> {
     return this.length === 0;
   }
 
-  public get(index: number): number {
+  public get(index: number): T {
     return this.data[index];
   }