Coin Kata for Paul DG

coin.clj

(ns cljdojo.coin
  (:require [clojure.test :refer :all]))

(def coins (sorted-set-by > 50 25 10 5 1))

(defn min-coins [total]
  (letfn [(step [[remaining tallies] coin]
           (let [decrements (->> (iterate #(- % coin) remaining)
                              (take-while #(>= % coin))
                              count)
                 remainder (- remaining (* coin decrements))
                 new-tallies (assoc tallies coin decrements)]
             (if (= 0 remainder)
                 (reduced new-tallies) ;; we're done
                 [remainder new-tallies])))]
     (reduce step [total {}] coins)))

(deftest roundtrip
  (are [total]
    (= total
       (reduce-kv (fn [sum coin count]
                   (+ sum (* coin count)))
               0
               (min-coins total)))
    44 88 100 25 37))

(comment (roundtrip))

I modified min-coins to take in the coins/denomination arg that it applies sorted-set-by and ran it through my test suite. Here are some of the errors:

FAIL in (kata-test) (core_test.clj:11)
Sub-dollar amounts with #{1 5 10 25}
expected: (= (coin-f denominations 55) {1 0, 5 1, 10 0, 25 2})
  actual: (not (= {5 1, 10 0, 25 2} {1 0, 5 1, 10 0, 25 2}))

FAIL in (kata-test) (core_test.clj:11)
Sub-dollar amounts with #{1 5 10 25}
expected: (= (coin-f denominations 80) {1 0, 5 1, 10 0, 25 3})
  actual: (not (= {5 1, 10 0, 25 3} {1 0, 5 1, 10 0, 25 3}))

FAIL in (kata-test) (core_test.clj:11)
Sub-dollar amounts with #{1 5 10 25}
expected: (= (coin-f denominations 0) {1 0, 5 0, 10 0, 25 0})
  actual: (not (= {25 0} {1 0, 5 0, 10 0, 25 0}))

FAIL in (kata-test) (core_test.clj:17)
Sub-dollar amounts with #{1 20 25}
expected: (= (coin-f denominations 80) {1 0, 20 4, 25 0})
  actual: (not (= {1 5, 20 0, 25 3} {1 0, 20 4, 25 0}))

FAIL in (kata-test) (core_test.clj:17)
Sub-dollar amounts with #{1 20 25}
expected: (= (coin-f denominations 0) {1 0, 20 0, 25 0})
  actual: (not (= {25 0} {1 0, 20 0, 25 0}))

FAIL in (kata-test) (core_test.clj:23)
Sub-dollar amounts with #{1 20 25 75}
expected: (= (coin-f denominations 80) {1 0, 20 4, 25 0, 75 0})
  actual: (not (= {1 5, 20 0, 25 0, 75 1} {1 0, 75 0, 20 4, 25 0}))