Ensure we have a test for single-edge sorting

[klahnakoski]

"edges":[{
		"allowNulls":false,
		"domain":{
			"interval":"week",
			"max":"today",
			"min":"today-1year",
			"type":"time",
			"sort":-1
		},
		"name":"date",
		"value":"action.end_time"
	}],