test.clj

(let [make-coercer (fn [schema coercion-matcher]
                     (spec/run-checker
                      (fn [s params]
                        (let [checker (spec/checker (s/spec s) params)]
                          (if-let [coercer (coercion-matcher s)]
                            (fn [x]
                              (macros/try-catchall
                                (let [check-result (checker x)]
                                  (if (utils/error? check-result)
                                    check-result
                                    (coercer check-result)))
                                (catch t (macros/validation-error s x t))))
                            checker)))
                      true
                      schema))
      schema {:date DateTime}
      value {:date (time/now)}
      coercion-matcher {DateTime (fn [date-time]
                                   (let [unix-timestamp (time-coerce/to-long date-time)]
                                     (* unix-timestamp DATE-TIME-CONVERSION-FACTOR)))}
      coercer (make-coercer schema coercion-matcher)]
  (coercer value))