@Test
public void testAuthSchemeNotSet() throws Exception {

    HttpRequest request = new BasicHttpRequest("GET", "/");
    HttpContext context = new BasicHttpContext();
    AuthState authstate = new AuthState();
    context.setAttribute(ClientContext.TARGET_AUTH_STATE, authstate);
    HttpRequestInterceptor interceptor = new RequestTargetAuthentication();
    interceptor.process(request, context);
    Header header = request.getFirstHeader(AUTH.WWW_AUTH_RESP);
    Assert.assertNull(header);
}