mockHolder[0] = mock;
            return mock;
        });
        req.header("Content-Type", "application/json");
        req.header("Authorization", "Bearer token123");

        // ## Act ##
        try (CurlResponse response = req.execute()) {
            // ## Assert ##
            Map<String, List<String>> props = mockHolder[0].getRecordedRequestProperties();

        // Add multiple headers
        request.header("Accept", "application/json").header("Content-Type", "application/json").header("Authorization", "Bearer token123")
                .header("X-Custom-Header", "custom-value");

        assertNotNull(request);
    }

    @Test
    public void testGzipSetsCompressionToGzip() {

        List<KuromojiItem> itemList = new ArrayList<>();
        itemList.add(new KuromojiItem(1, "token1", "seg1", "reading1", "pos1"));
        itemList.add(new KuromojiItem(2, "token2", "seg2", "reading2", "pos2"));
        itemList.add(new KuromojiItem(3, "token3", "seg3", "reading3", "pos3"));
        kuromojiFile.kuromojiItemList = itemList;
    }

    @Test
    public void test_selectList() {

        accessTokenHelper.setRandom(customRandom);

        final String token1 = accessTokenHelper.generateAccessToken();

        accessTokenHelper.setRandom(new Random(12345L));
        final String token2 = accessTokenHelper.generateAccessToken();

        assertEquals(token1, token2);
    }

    @Test
    public void test_generateAccessToken_withCustomRandom() {

        assertTrue(messages.hasMessageOf(property));
    }

    @Test
    public void test_addErrorsInvalidKuromojiSegmentation() {
        String property = "testProperty";
        String arg0 = "token1";
        String arg1 = "token2";
        FessMessages result = messages.addErrorsInvalidKuromojiSegmentation(property, arg0, arg1);
        assertNotNull(result);
        assertSame(messages, result);