Snippet to test motion activity data

TestCoreMotion.swift

        let df = DateFormatter()
        df.dateFormat = "yyyy-MM-dd HH:mm:ss Z"
        let startDate = df.date(from: "2017-09-27 14:50:19 +0000")!
        let endDate = df.date(from: "2017-09-27 15:14:28 +0000")!
        let cmm = CMMotionActivityManager()
        let lowestConfidence = CMMotionActivityConfidence.low
        cmm.queryActivityStarting(from: startDate, to: endDate, to: OperationQueue.main) {
            (activities, error) in
            
            guard let activities = activities else {
                return
            }
            print("------------------------")
            print("Confidence levels are low:\(CMMotionActivityConfidence.low.rawValue) - high:\(CMMotionActivityConfidence.high.rawValue)")
            print("Using confidence: \(lowestConfidence.rawValue)")
            print("\(startDate) - \(endDate)")
            print("start, time, confidence, stationary, unknown, walking, running, cycling, automotive")
            var lastEventDate = endDate
            var totalEventDate = endDate //for coalescing .unknown events for totals
            var map = [ActivityType: TimeInterval]()
            activities.reversed().forEach {
                (a) in
                
                guard a.confidence.rawValue >= lowestConfidence.rawValue else { return }
                
                let eventDuration = lastEventDate.timeIntervalSince(a.startDate)
                lastEventDate = a.startDate
                let values = [String(describing: a.startDate),
                              String(describing: eventDuration),
                              String(describing: a.confidence.rawValue),
                              String(describing: a.stationary),
                              String(describing: a.unknown),
                              String(describing: a.walking),
                              String(describing: a.running),
                              String(describing: a.cycling),
                              String(describing: a.automotive)]
                print(values.joined(separator: ", "))
                
                
                let type = ActivityType.from(motionActivity: a)
                if type != .unknown {
                    let totalDuration = totalEventDate.timeIntervalSince(a.startDate)
                    totalEventDate = a.startDate
                    if let current = map[type] {
                        map[type] = current + totalDuration
                    }
                    else {
                        map[type] = totalDuration
                    }
                }
            }
            
            print("Totals: \(map.debugDescription)")
            print("------------------------")
        }