Failing unit test for message with repeating group

message_test.go

@@ -146,6 +146,29 @@ func (s *MessageSuite) TestReBuild() {
 	s.True(bytes.Equal(s.msg.bodyBytes, expectedBodyBytes), "Incorrect body bytes, got %s", string(s.msg.bodyBytes))
 }
 
+func (s *MessageSuite) TestRebuildWithRepeatingGroup() {
+
+	dict, dictErr := datadictionary.Parse("spec/FIX44.xml")
+	s.Nil(dictErr)
+
+	// Given message bytes from a valid string
+	rawMsg := bytes.NewBufferString("8=FIX.4.4
9=210
35=D
34=2
347=UTF-8
52=20231231-20:19:41
49=01001
50=01001a
56=TEST
44=12
11=13976
1=10100400
21=1
386=1
336=NOPL
55=SYMABC
54=1
60=20231231-20:19:41
38=1
40=2
59=0
453=1
448=4501
447=D
452=28
354=6
355=Public
10=104
")
+
+	// When we parse it into a message
+	s.Nil(ParseMessageWithDataDictionary(s.msg, rawMsg, dict, dict))
+
+	// And then rebuild the message bytes
+	rebuildBytes := s.msg.build()
+
+	// this method does result in test passing. 
+	//s.msg.buildWithBodyBytes(s.msg.bodyBytes)
+
+	expectedBytes := []byte("8=FIX.4.4
9=210
35=D
34=2
49=01001
50=01001a
52=20231231-20:19:41
56=TEST
347=UTF-8
44=12
11=13976
1=10100400
21=1
386=1
336=NOPL
55=SYMABC
54=1
60=20231231-20:19:41
38=1
40=2
59=0
453=1
448=4501
447=D
452=28
354=6
355=Public
10=104
")
+
+	// Then the bytes should be the same with repeating group properly ordered
+	s.True(bytes.Equal(expectedBytes, rebuildBytes), "Unexpected bytes,\n +%s\n -%s", rebuildBytes, expectedBytes)
+}
+
 func (s *MessageSuite) TestReBuildWithRepeatingGroupForResend() {
 	// Given the following message with a repeating group
 	origHeader := "8=FIXT.1.1
9=161
35=8
34=3
49=ISLD
52=20240415-03:43:17.923
56=TW
"