Clojure 测试对于相同的预期值和实际值失败

Question

我正在做一个 Clojure 练习，基本上模拟汽车组装工厂。以下代码是我的“生产”代码。

(ns cars-assemble)

(def success-rate-frequencies [
  { :id 1 :interval #(= % 0), :rate 0 }
  { :id 2 :interval #(and (> % 0) (<= % 4)), :rate (/ 100 100) }
  { :id 3 :interval #(and (>= % 5) (<= % 8)), :rate (/ 90 100) }
  { :id 4 :interval #(= % 9), :rate (/ 80 100) }
  { :id 5 :interval #(>= % 10), :rate (/ 77 100) }
])

(defn get-rate-by-speed-interval [speed]
  (let [result (first (filter #((get % :interval) speed) success-rate-frequencies))]
    (get result :rate)))

(defn production-rate
  "Returns the assembly line's production rate per hour,
   taking into account its success rate"
  [speed]
  (float (* speed (* 221 (get-rate-by-speed-interval speed)))))

(defn working-items
  "Calculates how many working cars are produced per minute"
  [speed]
  (let [production-rate (production-rate speed)]
    (if (= speed 0) 0 (int (/ production-rate 60)))))

我的问题是，由于某种原因，当我运行测试时，生产代码返回正确的值，但测试仍然失败。下面我有我的测试示例。

(deftest production-rate-speed-10-test
(testing "Production rate for speed 10"
  (is (= 1701.7 (cars-assemble/production-rate 10)))))

这是我的命令lean test的输出：

FAIL in (production-rate-speed-10-test) (cars_assemble_test.clj:27)
Production rate for speed 10
expected: (= 1701.7 (cars-assemble/production-rate 10))
  actual: (not (= 1701.7 1701.7))

我试图检查它是否有任何隐藏字符，但没有找到任何东西。

我尝试过的另一件事是手动修改测试文件，将预期值转换为float（如下例所示）。但我不应该更改我的测试文件。

(is (= (float 1701.7) (cars-assemble/production-rate 10)))

Answer 1

= 函数检查参数是否具有相同的浮点值类型，因此当您实例化十进制数时，例如：

(def my-decimal-number 12.000)

您实际上是在实例化java.lang.Double。当您将其与 production-rate 函数返回的值进行比较时，您将收到一个错误，因为类型不同。只是更新函数production-rate 以返回double。

(defn production-rate
  "Returns the assembly line's production rate per hour,
   taking into account its success rate"
  [speed]
  (double (* speed (* 221 (get-rate-by-speed-interval speed)))))