package gateway

import "sort"

// keysOf returns the sorted keys of a map, for readable failure messages.
// (It used to live in the deleted billing-rules test file; other gateway tests
// still use it.)
func keysOf(m map[string]interface{}) []string {
	out := make([]string, 0, len(m))
	for k := range m {
		out = append(out, k)
	}
	sort.Strings(out)
	return out
}