Add tests for ProjectEuler problem 16 (Jest).

Project-Euler/test/Problem016.test.js

@@ -0,0 +1,16 @@
+const powerDigitSum = require('../Problem016')
+
+describe('Check Problem 16 - Power digit sum', () => {
+  it('Power digit sum of 2^15', () => {
+    expect(powerDigitSum(2, 15)).toBe(26)
+  })
+
+  it('Power digit sum of 2^1000', () => {
+    expect(powerDigitSum()).toBe(1366)
+    expect(powerDigitSum(2, 1000)).toBe(1366)
+  })
+
+  it('Power digit sum of 3^5000', () => {
+    expect(powerDigitSum(3, 5000)).toBe(11097)
+  })
+})