rendezvous with cassidoo challenge: 24.08.19

execution_times.clj

(ns execution-times
  "assumes each task/function is only run once
   and logs are clean so that the start and end 
   times of each task show up consecutively in 
   their respective order."
  (:require [clojure.test :refer [deftest is]]))

(defn calculate-execution-times [logs]
  (reduce (fn [acc [task1 task2]]
            (let [task  (:name task1)
                  start (:time task1)
                  end   (:time task2)
                  total (- end start)]
              (assoc acc task total)))
          {}
          (partition 2 2 (sort-by :name logs))))

(deftest calculate-execution-times-test                                                  
  (let [logs [{:name "main"     :time 0  :event "start"}
              {:name "subTask1" :time 5  :event "start"}
              {:name "subTask1" :time 10 :event "end"}
              {:name "subTask2" :time 15 :event "start"}
              {:name "subTask2" :time 20 :event "end"}
              {:name "main"     :time 25 :event "end"}]]
    (is (= { "main" 25, "subTask1" 5, "subTask2" 5}
           (calculate-execution-times logs)))))