assertEquals(ID_TOKEN_STRING, response.getIDToken().serialize());
assertEquals("abc", (String)response.getCustomParams().get("sub_sid"));
assertEquals(10, ((Number)response.getCustomParams().get("priority")).intValue());
assertEquals(2, response.getCustomParams().size());
HTTPResponse httpResponse = response.toHTTPResponse();
response = OIDCAccessTokenResponse.parse(httpResponse);
assertEquals("abc123", response.getAccessToken().getValue());
assertEquals("def456", response.getRefreshToken().getValue());