submap? - 递归检查一个映射是否在另一个映射中

Question

(submap? m1 m2) 递归检查 m1 是否包含在 m2 中

用法

(deftest submap
  (is (submap? {} {}))
  (is (not (submap? {:k 1} {})))
  (is (submap? {:k 1} {:k 1 :j 2}))
  (is (submap? {:k {:kk 1}} {:k {:kk 1 :j 2}}))
  (is (not (submap? {:k {:kk 1}} {:j 2}))))

这种需求通常在测试中出现，其中你想要检查被测试函数返回的映射具有特定的形状，同时在假设一个开放世界 - 即你想要忽略任何额外的键，这样改变被测试函数不会破坏测试

;; BAD: doesn't assume open world
(is (= {:k :v} (function-under-test)))

;; BAD: not expressive
(is (= :v (:k (function-under-test))))

;; BAD: not expressive, need to write :k twice
(is (= {:k :v} (select-keys (function-under-test) [:k])))

;; GOOD: expressive
(is (submap? {:k :v} (function-under-test)))

许多代码库中已经存在实现（在 GitHub 代码搜索中找到 400 多个结果）。示例

https://github.com/clojure/tools.deps/blob/ecc80420c1b734b384f7a42df91684cdbc37ddc6/src/test/clojure/clojure/tools/deps/util.clj#LL12-L25C18

https://github.com/ptaoussanis/encore/blob/96547700c03a5e81d784bcc9253980d7355f2f2b/src/taoensso/encore.cljc#L2071

Answer 1

登录https://clojure.atlassian.net/browse/CLJ-2755