Updated the test system

test/partialRight.test.js

@@ -0,0 +1,13 @@
+const expect = require('expect');
+const {partialRight} = require('./_30s.js');
+
+test('partialRight is a Function', () => {
+  expect(partialRight).toBeInstanceOf(Function);
+});
+function greet(greeting, name) {
+  return greeting + ' ' + name + '!';
+}
+const greetJohn = partialRight(greet, 'John');
+test('Appends arguments', () => {
+  expect(greetJohn('Hello')).toBe('Hello John!');
+});