Add solution for farm problem issue (#464)

src/battle_asserts/issues/farm_problem.clj

@@ -0,0 +1,33 @@
+(ns battle-asserts.issues.farm-problem
+  (:require [clojure.test.check.generators :as gen]))
+
+(def level :elementary)
+
+(def description "A farmer is asking you to tell him how many legs can be counted among all his animals.
+                  The farmer breeds three species:
+                  `chickens = 2 legs`
+                  `cows = 4 legs`
+                  `pigs = 4 legs`
+                  The farmer has counted his animals and he gives you a subtotal for each species.
+                  You have to implement a function that returns the total number of legs of all the animals.")
+
+(def signature
+  {:input [{:argument-name "chickens" :type {:name "integer"}}
+           {:argument-name "cows" :type {:name "integer"}}
+           {:argument-name "pigs" :type {:name "integer"}}]
+   :output {:type {:name "integer"}}})
+
+(defn arguments-generator
+  []
+  (gen/tuple gen/small-integer
+             gen/small-integer
+             gen/small-integer))
+
+(def test-data
+  [{:expected 36 :arguments [2 3 5]}
+   {:expected 22 :arguments [1 2 3]}
+   {:expected 50 :arguments [5 2 8]}])
+
+(defn solution
+  [chickens cows pigs]
+  (+ (* chickens 2) (* cows 4) (* pigs 4)))

test/battle_asserts/issues/farm_problem_test.clj

@@ -0,0 +1,15 @@
+(ns battle-asserts.issues.farm-problem-test
+  (:require [clojure.test :refer :all]
+            [clojure.test.check.properties :as prop]
+            [clojure.test.check.clojure-test :as ct]
+            [test-helper :as h]
+            [battle-asserts.issues.farm-problem :as issue]))
+
+(ct/defspec spec-solution
+  20
+  (prop/for-all [v (issue/arguments-generator)]
+                (instance? Number (apply issue/solution v))))
+
+(deftest test-solution
+  (h/generate-tests issue/test-data issue/solution))
+