private static void collectCustomRunners(
     Set<String> result,
     JSClass testClass,
     FlexUnitSupport flexUnitSupport,
     @Nullable Collection<JSClass> seen) {
   if (seen != null && seen.contains(testClass)) return;
   final String customRunner = FlexUnitSupport.getCustomRunner(testClass);
   if (!StringUtil.isEmptyOrSpaces(customRunner)) result.add(customRunner);
   if (flexUnitSupport.isSuite(testClass)) {
     if (seen == null) seen = new THashSet<>();
     seen.add(testClass);
     for (JSClass referencedClass : flexUnitSupport.getSuiteTestClasses(testClass)) {
       collectCustomRunners(result, referencedClass, flexUnitSupport, seen);
     }
   }
 }