Updated the test system

test/splitLines.test.js

@@ -0,0 +1,15 @@
+const expect = require('expect');
+const {splitLines} = require('./_30s.js');
+
+test('splitLines is a Function', () => {
+  expect(splitLines).toBeInstanceOf(Function);
+});
+test('Splits a multiline string into an array of lines.', () => {
+  expect(splitLines('This\nis a\nmultiline\nstring.\n')).toEqual([
+    'This',
+    'is a',
+    'multiline',
+    'string.',
+    ''
+  ]);
+});