run junit from clojure

junit.clj

(ns junit
  "could see as a modern replacement for lein-junit, which afaik does junit 4 at most.
  
  find and run some junit tests from clojure. 
  
  deps required are junit-jupiter, junit-jupiter-engine, junit-platform-launcher and junit-platform-reporting 
  "
  (:require [clojure.java.io :as io])
  (:import (java.nio.file Paths)
           (org.junit.platform.engine.discovery DiscoverySelectors)
           (org.junit.platform.launcher LauncherDiscoveryRequest TestExecutionListener)
           (org.junit.platform.launcher.core Launcher DiscoveryRequestBuilder LauncherFactory)
           (org.junit.platform.launcher.listeners LoggingListener SummaryGeneratingListener)
           .
           (org.junit.platform.reporting.legacy.xml LegacyXmlReportGeneratingListener)))

(defn run-junit
  "package arg is a string, which can be the first part of a package name. 
  so, 'com' would work, if you had packages starting 'com.widdindustries....'"
  [package]
  (let [discovery (-> (Launcher DiscoveryRequestBuilder/discoveryRequest)
                      (.selectors
                        [(DiscoverySelectors/selectPackage package)])
                      (.build))
        launcher (-> (LauncherFactory/openSession)
                     (.getLauncher))]
    (with-open [writer (PrintWriter-on (fn [s]) (fn []))]
      (let [test-plan (.discover launcher discovery)]
        (.execute launcher test-plan (into-array TestExecutionListener
                                       (LegacyXmlReportGeneratingListener. 
                                         (Paths/get (.toURI (io/file "test-results"))) 
                                         writer)))))))