public void CheckSumTest() { string str1 = "8=FIX.4.2\x01" + "9=45\x01" + "35=0\x01" + "34=3\x01" + "49=TW\x01" + "52=20000426-12:05:06\x01" + "56=ISLD\x01"; int chksum = 0; foreach (char c in str1) chksum += (int)c; chksum %= 256; str1 += "10=218\x01"; // checksum field Message msg = new Message(); try { msg.FromString(str1, true, null, null, _defaultMsgFactory); } catch (InvalidMessage e) { Assert.Fail("Unexpected exception (InvalidMessage): " + e.Message); } Assert.That(msg.CheckSum(), Is.EqualTo(chksum)); }