Test migration to jest by hand

Apparently using regular expressions is way easier.

test/randomHexColorCode/randomHexColorCode.js

@@ -0,0 +1,5 @@
+const randomHexColorCode = () => {
+let n = (Math.random() * 0xfffff * 1000000).toString(16);
+return '#' + n.slice(0, 6);
+};
+module.exports = randomHexColorCode;