A quick whack at the bowling kata

bowling.clj

(ns bowling.core
  (:use clojure.test))

(defn strike? [rolls]
  (= 10 (first rolls)))

(defn spare? [rolls]
  (= 10 (reduce + (take 2 rolls))))

(defn rolls-to-advance [rolls frame]
  (if (strike? rolls)
    (if (= 10 frame) 3 1) 2))

(defn items-in-frame [rolls]
  (cond (strike? rolls) 3
        (spare? rolls) 3
        :else 2))

(defn score [rolls]
  (loop [total 0
         frame 1
         rolls rolls]
    (if (not (empty? rolls))
      (recur (+ total (reduce + (take (items-in-frame rolls) rolls)))
             (inc frame)
             (drop (rolls-to-advance rolls frame) rolls))
      total)))

(deftest bowling
  (testing "gutterball game"
    (is (= 0 (score (repeat 20 0)))))
  (testing "game of all one pins"
    (is (= 20 (score (repeat 20 1)))))
  (testing "one spare"
    (is (= 22 (score '(5 5 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)))))
  (testing "one strike"
    (is (= 28 (score '(10 6 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)))))
  (testing "perfect game"
    (is (= 300 (score (repeat 12 10))))))