static String getJunitClsUrl(final boolean version4) {
    String url = version4 ? JavaSdkUtil.getJunit4JarPath() : JavaSdkUtil.getJunit3JarPath();
    final VirtualFile localFile = VirtualFileManager.getInstance().findFileByUrl(pathToUrl(url));
    if (localFile != null) {
      final VirtualFile jarFile = JarFileSystem.getInstance().getJarRootForLocalFile(localFile);
      url = jarFile != null ? jarFile.getUrl() : localFile.getUrl();
    }

    return url;
  }
 @NotNull
 @Override
 public List<String> getLibraryClassesRoots() {
   return Collections.singletonList(JavaSdkUtil.getJunit3JarPath());
 }
 @NotNull
 @Override
 public String getLibraryPath() {
   return JavaSdkUtil.getJunit3JarPath();
 }