Modified spec/assert for improved error reporting

assert.clj

(require '[clojure.spec.alpha :as spec])

;;; Spec does not report the name of the predicate when not wrapped in a spec.

(spec/assert number? nil)
;; Spec assertion failed val: nil fails predicate:
;; :clojure.spec.alpha/unknown :clojure.spec.alpha/failure
;; :assertion-failed


;;; But we can wrap predicates in specs so that their names are reported.

(defmacro assert'
  [spec x]
  (if spec/*compile-asserts*
    `(let [spec# (if (fn? ~spec)
                   (spec/spec ~spec)
                   ~spec)]
       (if clojure.lang.RT/checkSpecAsserts
         (spec/assert* (spec/specize* spec#) ~x)
         ~x))
    x))

(assert' number? 'a)
;; Spec assertion failed val: a fails predicate: number?
;; :clojure.spec.alpha/failure :assertion-failed