Test migration to jest by hand

Apparently using regular expressions is way easier.

test/isBrowser/isBrowser.js

@@ -0,0 +1,2 @@
+const isBrowser = () => ![typeof window, typeof document].includes('undefined');
+module.exports = isBrowser;

test/isBrowser/isBrowser.test.js

@@ -0,0 +1,8 @@
+const expect = require('expect');
+const isBrowser = require('./isBrowser.js');
+
+
+  test('isBrowser is a Function', () => {
+  expect(isBrowser).toBeInstanceOf(Function);
+});
+