### Question:
TokenHandler { public static Builder builder() { return new Builder(); } private  TokenHandler(Builder builder); static Builder builder(); static TokenHandler forHeader(String header); static TokenHandler create(Config config); Optional<String> extractToken(Map<String, List<String>> headers); String extractToken(String tokenRawValue); String tokenHeader(); void header(Map<String, List<String>> headers, String token); void addHeader(Map<String, List<String>> headers, String token);  }### Answer:
@Test public void testBuilder() { TokenHandler tp = TokenHandler.builder().tokenHeader("Authorization").build(); testBearer(tp, "bearer " + TOKEN_VALUE); }
@Test public void testWrongBuilder() { assertThrows(NullPointerException.class, () -> TokenHandler.builder() .tokenPattern(Pattern.compile("bearer (.*)", Pattern.CASE_INSENSITIVE)).build()); }