code: @Test public void testConstructor(){
    Throwable cause=new Exception();
    new HttpException();
    new HttpException("Oppsie");
    new HttpException("Oppsie",cause);
    new ProtocolException();
    new ProtocolException("Oppsie");
    new ProtocolException("Oppsie",cause);
    new NoHttpResponseException("Oppsie");
    new ConnectionClosedException("Oppsie");
    new MethodNotSupportedException("Oppsie");
    new MethodNotSupportedException("Oppsie",cause);
    new UnsupportedHttpVersionException();
    new UnsupportedHttpVersionException("Oppsie");
  }
  