Protobuf\Binary\Platform\InvalidNegativeEncoder::encodeSFixed64 PHP Method

    public function encodeSFixed64($sFixed64)
    {
        throw new RuntimeException("Negative integers are only supported with GMP or BC (64bit) intextensions.");
    }

 /**
  * @expectedException RuntimeException
  * @expectedExceptionMessage Negative integers are only supported with GMP or BC (64bit) intextensions.
  */
 public function testEncodeEncodeSFixed64Exception()
 {
     $encoder = new InvalidNegativeEncoder();
     $encoder->encodeSFixed64(-1);
 }