ThemeHelper mockThemeHelper = new ThemeHelper() {
            @Override
            protected Path getJarFile(Artifact artifact) {
                return jarPath;
            }
        };

        Artifact artifact = new Artifact("fess-theme-test", "1.0.0");
        Path result = mockThemeHelper.getJarFile(artifact);
        assertEquals(jarPath, result);
    }

    @Test

     *
     * @param artifact the theme artifact to install
     * @throws ThemeException if installation fails
     */
    public void install(final Artifact artifact) {
        final Path jarPath = getJarFile(artifact);
        final String themeName = getThemeName(artifact);
        if (logger.isDebugEnabled()) {
            logger.debug("Theme: name={}", themeName);
        }

                } else if ("jar".equals(resource.getProtocol())) {
                    final JarURLConnection jarURLConnection = (JarURLConnection) resource.openConnection();
                    try (JarFile jarFile = jarURLConnection.getJarFile()) {
                        final Enumeration<JarEntry> entries = jarFile.entries();
                        while (entries.hasMoreElements()) {
                            final JarEntry entry = entries.nextElement();