Added jest

.gitignore

@@ -1 +1,2 @@
-.vscode
+.vscode
+node_modules

helloWorld/helloWorld.js

@@ -2,4 +2,4 @@ const helloWorld = function() {
   return ''
 }
 
-module.exports = helloWorld
+module.exports = helloWorld;

helloWorld/helloWorld.spec.js

@@ -1,7 +1,12 @@
+const { expect } = require('@jest/globals');
 const helloWorld = require('./helloWorld');
 
-describe('Hello World', function() {
+// describe('Hello World', function() {
-  it('says hello world', function() {
+//   it('says hello world', function() {
-    expect(helloWorld()).toEqual('Hello, World!');
+//     expect(helloWorld()).toEqual('Hello, World!');
-  });
+//   });
-});
+// });
+
+test('says "Hello, World!"', () => {
+  expect(helloWorld()).toBe("Hello, World!");
+});

package.json

@@ -0,0 +1,8 @@
+{
+  "devDependencies": {
+    "jest": "^26.6.3"
+  },
+  "scripts": {
+    "test": "jest"
+  }
+}