Temporal is a testing library inspired by Temporal Logic
An ideal use case is for testing cooperation of systems in time, even running on different computers (like microservices, SOA).
With temporal, it is easy to test for situations like:
- Events X in service A should always happen before events Y in a service B.
- There should be exactly 3 events T in any of our services A, B, and C.
- Event P on any service never happens at the same time as event Q on any service.
As there's a centralized service collecting events that expect just simple POST event={event name}, it's trivially easy for you to add a support for more programming languages if needed.
(temporal.core/start-server 6589) ; running on http://localhost:6589
Then any POST request to (base url)/add-event with parameter event={name} is saved.
You can get your timeline at (base url)/get-timeline
You can reset state with (base url)/reset-timeline
Example of test using temporal:
(ns temporal.core-test
(:require [clojure.test :refer :all]
[temporal.core :as tl]
[clj-http.client :as http]
[clojure.edn :as edn]))
(defn get-http-timeline [base-url]
(-> (http/get (str base-url "/get-timeline"))
:body
edn/read-string))
(defn reset-http-timeline [base-url]
(http/post (str base-url "/reset-timeline")))
(deftest test-a-happens-after-b
(reset-http-timeline "http://localhost:6589")
(tl/add-event :event-1)
(tl/add-event :event-2)
(tl/add-event :event-3)
(tl/add-event :event-4)
(let [http-timeline (get-http-timeline "http://localhost:6589")]
(testing "event-1 should happen before event-2"
(is (tl/a-happens-after-b http-timeline :event-2 :event-1)))
(testing "event-2 should happen before event-3"
(is (tl/a-happens-after-b http-timeline :event-3 :event-2)))
(testing "event-3 should happen before event-4"
(is (tl/a-happens-after-b http-timeline :event-4 :event-3)))
(testing "event-4 should not happen before event-1"
(is (not (tl/a-happens-after-b http-timeline :event-1 :event-4))))))
You can easily create your own combinators. Below are current combinators Temporal supports:
(defn a-happens-after-b [timeline event-a event-b]
(> (.indexOf timeline event-a)
(.indexOf timeline event-b)))
(defn a-happens-before-b [timeline event-a event-b]
(< (.indexOf timeline event-a)
(.indexOf timeline event-b)))
(defn a-and-b-are-consecutive [timeline event-a event-b]
(= 1 (- (.indexOf timeline event-b)
(.indexOf timeline event-a))))
(defn a-happens-immediately-before-b [timeline event-a event-b]
(a-and-b-are-consecutive timeline event-a event-b))
(defn a-happens-immediately-after-b [timeline event-a event-b]
(a-and-b-are-consecutive timeline event-b event-a))
(defn a-happens-n-times [timeline event n]
(= n (count (filter #(= % event) timeline))))
(defn a-happens-at-least-n-times [timeline event n]
(>= (count (filter #(= % event) timeline)) n))
(defn a-happens-at-most-n-times [timeline event n]
(<= (count (filter #(= % event) timeline)) n))
(defn a-happens-exactly-n-times [timeline event n]
(a-happens-n-times timeline event n))
(defn a-never-happens [timeline event]
(a-happens-n-times timeline event 0))
(defn a-always-happens [timeline event]
(every? #(= % event) timeline))
(defn a-happens-before-b-n-times [timeline event-a event-b n]
(= n (count (filter #(and (= % event-a)
(a-happens-before-b timeline event-a event-b))
timeline))))
(defn a-happens-after-b-n-times [timeline event-a event-b n]
(= n (count (filter #(and (= % event-a)
(a-happens-after-b timeline event-a event-b))
timeline))))
(defn a-or-b-happens [timeline event-a event-b]
(or (some #(= % event-a) timeline)
(some #(= % event-b) timeline)))
(defn a-and-b-happen [timeline event-a event-b]
(and (some #(= % event-a) timeline)
(some #(= % event-b) timeline)))
(defn a-and-b-never-happen-together [timeline event-a event-b]
(not-any? #(= % [event-a event-b]) (partition 2 1 timeline)))
(defn a-happens-within-n-events-of-b [timeline event-a event-b n]
(some #(<= (Math/abs (- %1 %2)) n)
(.indexOf timeline event-a)
(.indexOf timeline event-b)))
(defn a-happens-between-b-and-c [timeline event-a event-b event-c]
(let [b-index (.indexOf timeline event-b)
c-index (.indexOf timeline event-c)
a-index (.indexOf timeline event-a)]
(and (< b-index a-index) (< a-index c-index))))
(defn a-happens-before-all [timeline event events]
(every? #(a-happens-before-b timeline event %) events))
(defn a-happens-after-all [timeline event events]
(every? #(a-happens-after-b timeline event %) events))
(defn a-happens-immediately-before-any [timeline event-a events]
(some #(a-happens-immediately-before-b timeline event-a %) events))
(defn a-happens-immediately-after-any [timeline event-a events]
(some #(a-happens-immediately-after-b timeline event-a %) events))
(defn a-happens-exactly-n-times-between-b-and-c [timeline event-a event-b event-c n]
(let [b-index (.indexOf timeline event-b)
c-index (.indexOf timeline event-c)
a-indices (keep-indexed #(when (= %2 event-a) %1) timeline)]
(= n (count (filter #(and (< b-index %) (< % c-index)) a-indices)))))
(defn a-happens-at-least-n-times-between-b-and-c [timeline event-a event-b event-c n]
(let [b-index (.indexOf timeline event-b)
c-index (.indexOf timeline event-c)
a-indices (keep-indexed #(when (= %2 event-a) %1) timeline)]
(>= (count (filter #(and (< b-index %) (< % c-index)) a-indices)) n)))
(defn a-happens-at-most-n-times-between-b-and-c [timeline event-a event-b event-c n]
(let [b-index (.indexOf timeline event-b)
c-index (.indexOf timeline event-c)
a-indices (keep-indexed #(when (= %2 event-a) %1) timeline)]
(<= (count (filter #(and (< b-index %) (< % c-index)) a-indices)) n)))
(defn all-of-events-happen [timeline events]
(every? #(some #(= % %2) timeline) events))
(defn none-of-events-happen [timeline events]
(not-any? #(some #(= % %2) timeline) events))
(defn events-happen-in-order [timeline events]
(let [event-indices (map #(keep-indexed #(when (= %2 %1) %1) timeline) events)]
(= event-indices (sort event-indices))))
(defn a-happens-before-b-or-c [timeline event-a event-b event-c]
(or (a-happens-before-b timeline event-a event-b)
(a-happens-before-b timeline event-a event-c)))
(defn a-happens-after-b-or-c [timeline event-a event-b event-c]
(or (a-happens-after-b timeline event-a event-b)
(a-happens-after-b timeline event-a event-c)))
(defn a-and-b-happen-consecutively-n-times [timeline event-a event-b n]
(= n (count (filter #(and (= % event-a)
(a-happens-immediately-before-b timeline event-a event-b))
timeline))))
(defn a-happens-between-b-and-c-n-times [timeline event-a event-b event-c n]
(let [a-indices (keep-indexed #(when (= %2 event-a) %1) timeline)
b-indices (keep-indexed #(when (= %2 event-b) %1) timeline)
c-indices (keep-indexed #(when (= %2 event-c) %1) timeline)]
(= n (count (filter
#(let [a-index %]
(some
#(and (< % a-index) (some #(> % a-index) c-indices))
b-indices))
a-indices)))))
(defn a-happens-immediately-before-b-or-c [timeline event-a event-b event-c]
(or (a-happens-immediately-before-b timeline event-a event-b)
(a-happens-immediately-before-b timeline event-a event-c)))
(defn a-happens-immediately-after-b-or-c [timeline event-a event-b event-c]
(or (a-happens-immediately-after-b timeline event-a event-b)
(a-happens-immediately-after-b timeline event-a event-c)))
(defn a-happens-immediately-before-b-and-c [timeline event-a event-b event-c]
(and (a-happens-immediately-before-b timeline event-a event-b)
(a-happens-immediately-before-b timeline event-a event-c)))
(defn a-happens-immediately-after-b-and-c [timeline event-a event-b event-c]
(and (a-happens-immediately-after-b timeline event-a event-b)
(a-happens-immediately-after-b timeline event-a event-c)))
(defn a-b-and-c-happen-consecutively [timeline event-a event-b event-c]
(and (a-happens-immediately-before-b timeline event-a event-b)
(a-happens-immediately-before-b timeline event-b event-c)))
(defn a-b-and-c-happen-in-any-order [timeline event-a event-b event-c]
(let [indices (map #(keep-indexed #(when (= %2 %1) %1) timeline) [event-a event-b event-c])]
(every? (partial < -1) (apply map + indices))))
(defn a-happens-before-b-and-c [timeline event-a event-b event-c]
(and (a-happens-before-b timeline event-a event-b)
(a-happens-before-b timeline event-a event-c)))
(defn a-happens-after-b-and-c [timeline event-a event-b event-c]
(and (a-happens-after-b timeline event-a event-b)
(a-happens-after-b timeline event-a event-c)))
(defn a-b-and-c-happen-together [timeline event-a event-b event-c]
(let [event-set #{event-a event-b event-c}]
(some #(= event-set (set (subvec timeline % (+ % 3))))
(range 0 (- (count timeline) 2)))))
(defn a-happens [timeline event-a]
(some #(= % event-a) timeline))
(defn a-happens-n-times [timeline event-a n]
(= n (count (filter #(= % event-a) timeline))))
(defn a-happens-at-least-n-times [timeline event-a n]
(>= (count (filter #(= % event-a) timeline)) n))
(defn a-happens-at-most-n-times [timeline event-a n]
(<= (count (filter #(= % event-a) timeline)) n))
(defn a-happens-within-n-time-units [timeline event-a n]
(<= (.indexOf timeline event-a) n))
(defn a-happens-after-n-time-units [timeline event-a n]
(>= (.indexOf timeline event-a) n))
(defn a-happens-exactly-n-time-units-apart [timeline event-a n]
(let [a-indices (keep-indexed #(when (= %2 event-a) %1) timeline)]
(every? #(= (first %) (- (second %) n))
(partition 2 1 a-indices))))
(defn a-happens-at-least-n-time-units-apart [timeline event-a n]
(let [a-indices (keep-indexed #(when (= %2 event-a) %1) timeline)]
(every? #(<= (first %) (- (second %) n))
(partition 2 1 a-indices))))
(defn a-happens-at-most-n-time-units-apart [timeline event-a n]
(let [a-indices (keep-indexed #(when (= %2 event-a) %1) timeline)]
(every? #(>= (first %) (- (second %) n))
(partition 2 1 a-indices))))
(defn a-happens-after-any-event [timeline event-a]
(some #(= % event-a) (rest timeline)))- make integration with clojure.test easier (0.3)
- provide base_url & port as a parameter everywhere (0.4)
- consider adding not only event to the timeline, but also a service so assertions can be made on a service too (0.5)
- write tests for all combinators (0.6)
- test it with our services and improve usability (0.7)
- consider a generator of tests based on temporal-logic-like spec (temporal specs -> Instaparse -> tests) (0.8)
- make parallel running of more tests easier (0.9)
- document properly (1.0)
Copyright © 2023
This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at http://www.eclipse.org/legal/epl-2.0.
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