Database function test case

gistfile1.clj

(ns scratch.db-fns-test-case
  (:require 
    [datomic.api :refer (q db) :as d]))

(def test-state (atom 
                  {:db-str "datomic:free://localhost:4334/somedb" 
                   ;:db-str"datomic:mem://test"
                   }))

(swap! test-state 
  (fn [{:keys [db-str] :as ts}]
    (when (.contains db-str "datomic:mem")
      (d/create-database db-str))
    (assoc ts :connection (d/connect db-str))))

(let [conn (:connection @test-state)] 
  
  (d/transact conn 
    [{:db/ident :user/next-id
      :db/valueType :db.type/long
      :db/id #db/id[:db.part/db]
      :db/cardinality :db.cardinality/one
      :db.install/_attribute :db.part/db
      :db/noHistory true}])
  
  (d/transact conn
   [{:db/ident :user/order-number-sequence
     :user/next-id 10000 ; this is the first order number
     :db/id #db/id[:db.part/user -1000]}])
  
  (d/transact conn 
    [{:db/id (d/tempid :db.part/user)
      :db/ident :user/inc
      :db/fn (d/function 
               '{:lang "clojure"
                 :params [db eid]
                 :code "(let [s (d/entity db eid)] 
                           [{:db/id (:db/id s) 
                             :user/next-id (inc (:user/next-id s))}])"})}])
  
  (let [s (d/touch (d/entity (d/db conn) :user/order-number-sequence))
        {:keys [db-after]} @(d/transact conn [[:user/inc (:db/id s)]])
        s-after-inc (d/entity db-after :user/order-number-sequence)]
    (assert (= 10001 (:user/next-id s-after-inc)) "next-id shoudl be incremented"))
  :done)