Test migration to jest by hand

Apparently using regular expressions is way easier.

test/functions/functions.js

@@ -0,0 +1,6 @@
+const functions = (obj, inherited = false) =>
+(inherited
+? [...Object.keys(obj), ...Object.keys(Object.getPrototypeOf(obj))]
+: Object.keys(obj)
+).filter(key => typeof obj[key] === 'function');
+module.exports = functions;