@Test
    public void test_decodeBase64_urlSafe() {
        // Base64 URL encoding (uses - and _ instead of + and /)
        final byte[] result = authenticator.decodeBase64("SGVsbG9Xb3JsZA");
        assertEquals("HelloWorld", new String(result));
    }

    @Test
    public void test_decodeBase64_withPadding() {
        // Standard Base64 with padding
        final byte[] result = authenticator.decodeBase64("dGVzdA==");

    public void test_evaluate_stringOperations() {
        final Map<String, Object> params = new HashMap<>();
        params.put("first", "Hello");
        params.put("second", "World");

        assertEquals("HelloWorld", groovyEngine.evaluate("return first + second", params));
        assertEquals("HELLO", groovyEngine.evaluate("return first.toUpperCase()", params));
        assertEquals(5, groovyEngine.evaluate("return first.length()", params));