public static String fillChars(char ch, int count) {
        if (count <= 0) {
            return "";
        } else {
            return Character.toString(ch).repeat(count);
        }
    }
@Test
    public void testFillChars() {
        assertEquals("", StringHelper.fillChars('-', 0));
        assertEquals("==", StringHelper.fillChars('=', 2));
        assertEquals("----", StringHelper.fillChars('-', 4));
        assertEquals("..........", StringHelper.fillChars('.', 10));
    }