[Testing] Add jest to modules

.husky/pre-push

@@ -0,0 +1,4 @@
+#!/bin/sh
+. "$(dirname "$0")/_/husky.sh"
+
+yarn test

README.md

@@ -10,27 +10,31 @@ See wiki for details: https://github.com/source-academy/modules/wiki
 
 1. Install a stable version of [NodeJS](https://nodejs.org/en/). The active LTS or current version should work fine.
 2. Install a stable version of [Yarn](https://yarnpkg.com/).
+
 ```
 $ npm install -g yarn
 ```
+
 3. Clone this repository and navigate to it in your command line or shell tool.
+
 ```
 $ git clone https://github.com/source-academy/modules.git
 $ cd modules
 ```
+
 4. Run `yarn install` to install dependencies.
 
 ### Serving the Modules' JavaScript Files
 
 1. Run `yarn run build` to transpile the modules' files from `src` folder into `build` folder.
-2. Run `yarn serve` to start the http-server on http://localhost:8022 to serve the `.js` files in `build` folder.
+2. Run `yarn serve` to start the http-server on http://localhost:8022 to serve all files in the `build` folder with the same directory structure.
 
 ### Using with Cadet Frontend
 
 1. Follow the [setup](https://github.com/source-academy/cadet-frontend#getting-started) instructions on Cadet Frontend.
-2. When [setting up](https://github.com/source-academy/cadet-frontend#getting-started) the backend configuration of Cadet Frontend, ensure that `REACT_APP_MODULE_BACKEND_URL=http://localhost:8022` from the subsection above. 
-3. Ensure that you are serving the modules' javascript files in a local server. Refer to the subsection above for instructions. 
-4. [Start up](https://github.com/source-academy/cadet-frontend#getting-started) the Cadet Frontend local development server to use the served modules. 
+2. When [setting up](https://github.com/source-academy/cadet-frontend#getting-started) the backend configuration of Cadet Frontend, ensure that `REACT_APP_MODULE_BACKEND_URL=http://localhost:8022` from the subsection above.
+3. Ensure that you are serving the modules' javascript files in a local server. Refer to the subsection above for instructions.
+4. [Start up](https://github.com/source-academy/cadet-frontend#getting-started) the Cadet Frontend local development server to use the served modules.
 
 ## License
 

package.json

@@ -4,27 +4,41 @@
   "version": "1.0.0",
   "repository": "https://github.com/source-academy/modules.git",
   "license": "Apache-2.0",
+  "scripts-info": {
+    "module": "Add a new bundle or tab",
+    "lint": "Check code for errors",
+    "lint:fix": "Automatically fix lint errors",
+    "build": "Transpile modules' files from src folder to build folder",
+    "serve": "Start the http-server to serve all files in the build folder with the same directory structure",
+    "prepare": "Enable git hooks",
+    "test": "Run unit tests",
+    "test:watch": "Watch files for changes and rerun tests related to changed files"
+  },
   "scripts": {
     "module": "node ./templates/app.js",
     "lint": "./node_modules/.bin/eslint --config ./.eslintrc.js --ext \".ts, .tsx\" src",
     "lint:fix": "./node_modules/.bin/eslint --config ./.eslintrc.js --ext \".ts, .tsx\" src --fix",
     "build": "yarn lint && ./node_modules/.bin/tsc && rollup --config rollup.config.js",
     "serve": "http-server --cors=* -c-1 -p 8022 ./build",
-    "prepare": "husky install"
+    "prepare": "husky install",
+    "test": "jest --verbose",
+    "test:watch": "jest --watch"
   },
   "devDependencies": {
     "@babel/cli": "^7.13.10",
-    "@babel/core": "^7.13.10",
-    "@babel/preset-env": "^7.13.10",
+    "@babel/core": "^7.13.13",
+    "@babel/preset-env": "^7.13.12",
     "@babel/preset-react": "^7.12.13",
     "@babel/preset-typescript": "^7.13.0",
     "@rollup/plugin-babel": "^5.3.0",
     "@rollup/plugin-node-resolve": "^11.2.0",
     "@rollup/plugin-typescript": "^8.2.0",
+    "@types/jest": "^26.0.22",
     "@types/node": "^14.14.34",
     "@types/react": "^17.0.3",
     "@typescript-eslint/eslint-plugin": "^4.17.0",
     "@typescript-eslint/parser": "^4.17.0",
+    "babel-jest": "^26.6.3",
     "eslint": "^7.22.0",
     "eslint-config-airbnb-typescript": "^12.3.1",
     "eslint-config-prettier": "^8.1.0",
@@ -37,13 +51,15 @@
     "generate-template-files": "^3.0.0",
     "http-server": "^0.12.3",
     "husky": "5",
+    "jest": "^26.6.3",
     "prettier": "^2.2.1",
     "rollup": "^2.41.2",
     "rollup-plugin-babel": "^4.4.0",
     "rollup-plugin-commonjs": "^10.1.0",
     "rollup-plugin-copy": "^3.4.0",
     "rollup-plugin-filesize": "^9.1.1",
     "rollup-plugin-inject-process-env": "^1.3.1",
+    "ts-jest": "^26.5.4",
     "typescript": "^4.2.3",
     "yarnhook": "^0.5.1"
   },
@@ -60,5 +76,12 @@
   },
   "peerDependencies": {
     "tslib": "^2.1.0"
+  },
+  "jest": {
+    "roots": [
+      "<rootDir>/src/bundles",
+      "<rootDir>/src/tabs",
+      "<rootDir>/templates"
+    ]
   }
 }

src/bundles/repeat/__tests__/index.ts

@@ -0,0 +1,17 @@
+import Repeat from '../index';
+
+// Destructure functions exported from bundle
+const { repeat, twice, thrice } = Repeat();
+
+// Test functions
+test('repeat works correctly and repeats function n times', () => {
+  expect(repeat((x: number) => x + 1, 5)(1)).toBe(6);
+});
+
+test('twice works correctly and repeats function twice', () => {
+  expect(twice((x: number) => x + 1)(1)).toBe(3);
+});
+
+test('thrice works correctly and repeats function thrice', () => {
+  expect(thrice((x: number) => x + 1)(1)).toBe(4);
+});

src/bundles/repeat/index.ts

@@ -4,19 +4,38 @@
  * @author Tang Xin Kye, Marcus
  */
 
-// eslint-disable-next-line no-underscore-dangle
-function repeat(f: Function, n: any) {
+/**
+ * Repeats function n times
+ *
+ * @param f - function to be repeated
+ * @param n - number of times to be repeated
+ * @return a function repeated n times
+ */
+function repeat(f: Function, n: any): Function {
   return n === 0 ? (x: any) => x : (x: any) => f(repeat(f, n - 1)(x));
 }
 
-function twice(f: any) {
+/**
+ * Repeats function twice
+ *
+ * @param f - function to be repeated
+ * @return a function repeated twice
+ */
+function twice(f: Function): Function {
   return repeat(f, 2);
 }
 
-function thrice(f: any) {
+/**
+ * Repeats function thrice
+ *
+ * @param f - function to be repeated
+ * @return a function repeated thrice
+ */
+function thrice(f: Function): Function {
   return repeat(f, 3);
 }
 
+// exported functions from the bundle
 export default () => ({
   repeat,
   twice,

tsconfig.json

@@ -27,7 +27,7 @@
     /* The target setting changes which JS features are downleveled and which are left intact. */
     "target": "es5",
     /* By default all visible ”@types” packages are included in your compilation. */
-    "types": ["node"],
+    "types": ["node", "jest"],
     /* In some cases where no type annotations are present, TypeScript will fall back to a type of any for a variable when it cannot infer the type. */
     /* *** TEMPORARILY ADDED UNTIL ALL MODULES HAVE BEEN REFACTORED!!!!!!!!!!! *** */
     "noImplicitAny": false,