Test migration to jest by hand

Apparently using regular expressions is way easier.

test/inRange/inRange.js

@@ -0,0 +1,5 @@
+const inRange = (n, start, end = null) => {
+if (end && start > end) end = [start, (start = end)][0];
+return end == null ? n >= 0 && n < start : n >= start && n < end;
+};
+module.exports = inRange;