add test for multiple repeating groups in a message

partly revert change in quickfixgo#368 due to breaking the unit test added in this PR

validation.go

@@ -246,7 +246,6 @@ func validateVisitGroupField(fieldDef *datadictionary.FieldDef, fieldStack []Tag
 			if childDefs[0].Required() {
 				return fieldStack, RequiredTagMissing(Tag(childDefs[0].Tag()))
 			}
-			fieldStack = fieldStack[1:]
 		}
 
 		childDefs = childDefs[1:]

validation_test.go

@@ -74,6 +74,7 @@ func TestValidate(t *testing.T) {
 		tcInvalidTagCheckDisabledFixT(),
 		tcInvalidTagCheckEnabled(),
 		tcInvalidTagCheckEnabledFixT(),
+		tcMultipleRepeatingGroupFields(),
 	}
 
 	msg := NewMessage()
@@ -923,6 +924,17 @@ func tcFloatValidationFixT() validateTest {
 	}
 }
 
+func tcMultipleRepeatingGroupFields() validateTest {
+	dict, _ := datadictionary.Parse("spec/FIX43.xml")
+	validator := NewValidator(defaultValidatorSettings, dict, nil)
+	return validateTest{
+		TestName:             "Multiple repeating group fields in a message",
+		Validator:            validator,
+		MessageBytes:         []byte("8=FIX.4.3
9=176
35=D
34=2
49=TW
52=20140329-22:38:45
56=ISLD
11=ID
453=2
448=PARTYID
452=3
523=SUBID
448=PARTYID2
452=3
78=1
79=ACCOUNT
80=1
21=1
40=1
54=1
38=200
55=INTC
60=20140329-22:38:45
10=178
"),
+		DoNotExpectReject:    true,
+	}
+}
+
 func TestValidateVisitField(t *testing.T) {
 	fieldType0 := datadictionary.NewFieldType("myfield", 11, "STRING")
 	fieldDef0 := &datadictionary.FieldDef{FieldType: fieldType0}