Clojure“是”声明未按预期工作

Question

我正在为我的第一个Clojure项目编写测试用例。在这里，如果“：meat”的值为空，我希望测试失败：

(deftest order-sandwich
  (let [response {:meat "" :bread "yes" :add-on "lettuce"}]
    (is (= (:bread response) "yes"))
    (is (not (nil? (:meat response))))))

但是我的测试运行成功（返回“ nil”）。

有人知道为什么会这样吗？有一个更好的方法吗？

我提前谢谢你！！

Answer 1

An empty String is not nil:

(nil? "")
=> false

You want to test if it's empty, not nil, which can be done using seq or empty? (among other ways):

(is (not (empty? (:meat response))))
; Or use not-empty

; There's also the arguably more idiomatic way

(is (seq (:meat response)))