Updated the test system

test/randomNumberInRange.test.js

@@ -0,0 +1,15 @@
+const expect = require('expect');
+const {randomNumberInRange} = require('./_30s.js');
+
+test('randomNumberInRange is a Function', () => {
+  expect(randomNumberInRange).toBeInstanceOf(Function);
+});
+const lowerLimit = Math.floor(Math.random() * 20);
+const upperLimit = Math.floor(lowerLimit + Math.random() * 10);
+test('The returned value is a number', () => {
+  expect(typeof randomNumberInRange(lowerLimit, upperLimit) === 'number').toBeTruthy();
+});
+const numberForTest = randomNumberInRange(lowerLimit, upperLimit);
+test('The returned value lies between provided lowerLimit and upperLimit (both inclusive).', () => {
+  expect(numberForTest >= lowerLimit && numberForTest <= upperLimit).toBeTruthy();
+});