Test migration to jest by hand

Apparently using regular expressions is way easier.

test/extendHex/extendHex.js

@@ -0,0 +1,8 @@
+const extendHex = shortHex =>
+'#' +
+shortHex
+.slice(shortHex.startsWith('#') ? 1 : 0)
+.split('')
+.map(x => x + x)
+.join('');
+module.exports = extendHex;