@Test
public void testExecute() throws Exception {

    CurrencyCodeSanitizer sanitizer = new CurrencyCodeSanitizer();
    assertEquals("USD", sanitizer.execute("USD"));
    assertEquals("USD", sanitizer.execute("usd"));
    assertEquals("EUR", sanitizer.execute("EUR"));
    assertEquals("", sanitizer.execute(""));
    assertEquals(" ", sanitizer.execute(" "));
    assertEquals(null, sanitizer.execute(null));
    assertEquals("USD", sanitizer.execute("abc"));
    assertEquals("USD", sanitizer.execute("abcd"));
    assertEquals("USD", sanitizer.execute("1234"));
    assertEquals("USD", sanitizer.execute("!?"));
    assertEquals("USD", sanitizer.execute("<script>"));
}