GCD function and more tests

.gitignore

@@ -1,2 +1,3 @@
 node_modules
 .DS_Store
+.idea/

sketch.js

@@ -1,36 +1,46 @@
 function sum(a, b) {
-  return a + b;
+    return a + b;
 }
 
-function sayHelloTo(username){
-  return "Hello, " + username + "!";
+function sayHelloTo(username) {
+    return "Hello, " + username + "!";
 }
 
-function sub(a, b){
-  return a - b; 
+function sub(a, b) {
+    return a - b;
 }
 
 function prod(a, b) {
-  return a * b;
+    return a * b;
 }
 
 function answer() {
-  return 42;
+    return 42;
 }
 
 function digital_root(n) {
-  return (n-1)%9+1;
+    return (n - 1) % 9 + 1;
 }
+
 function sum42(a, b) {
-  return a + b + 42;
+    return a + b + 42;
+}
+
+function findGcd(a, b) {
+    if (!b) {
+        return a;
+    }
+
+    return findGcd(b, a % b);
 }
 
 module.exports = {
-  sum: sum,
-  sub: sub,
-  prod: prod,
-  sum42: sum42,
-  digital_root: digital_root,
-  hello: sayHelloTo,
-  answer: answer
+    sum: sum,
+    sub: sub,
+    prod: prod,
+    sum42: sum42,
+    digital_root: digital_root,
+    hello: sayHelloTo,
+    answer: answer,
+    gcd: findGcd
 }

sketch.test.js

@@ -1,59 +1,21 @@
-const { sum, prod, digital_root, sum42 } = require('./sketch');
+const {sum, prod, digital_root, sum42, gcd} = require('./sketch');
 
 // test('adds 1 + 2 to equal 3', () => {
 //   expect(sum(1, 2)).toBe(3);
 // });
 
-/**
- * Sum to be defined
- */
-
-test('Sum function exists', () => {
-  expect(sum).toBeDefined();
-});
-
 test('adds 1 + 2 to equal 3', sumTest);
 
 function sumTest() {
-  expect(sum(1, 2)).toBe(3);
+    expect(sum(1, 2)).toBe(3);
 }
 
 function helloTest() {
-  expect(sayHelloTo("Dan")).toBe("Hello, Dan!");
+    expect(sayHelloTo("Dan")).toBe("Hello, Dan!");
 }
 
-/**
- * Prod to be defined
- */
-
-test('Prod function exists',()=>{
-  expect(prod).toBeDefined();
-});
-
-/**
- * prod function output
- */
-
-test('prod calculates 2 * 10 = 20', () => {
-  expect(prod(2, 10)).toBe(20);
-});
-
-/**
- * Digital Root to be defined
- */
-
- test('digital_root function exists', ()=>{
-  expect('digital_root').toBeDefined();
- });
-
-test('digital root of 265 should equal 4', () => {
-  expect(digital_root(265)).toBe(4);
-})
-
-test('Sum42 function exists', () => {
-  expect(sum42).toBeDefined();
-});
+test('GCD of 40 and 20', gcdSimpleTest);
 
-test('Sum42 3 + 1 should be 46', () => {
-  expect(sum42(3, 1)).toBe(46);
-});
+function gcdSimpleTest() {
+    expect(gcd(20, 40)).toBe(20);
+}