[tests] enhance Cert_6_1_02_REEDAttach_MED/SED (#3387)

tests/scripts/thread-cert/message.py

@@ -303,6 +303,9 @@ class Message(object):
     def assertSentWithHopLimit(self, hop_limit):
         assert self.ipv6_packet.ipv6_header.hop_limit == hop_limit
 
+    def isMacAddressTypeLong(self):
+        return self.mac_header.dest_address.type == common.MacAddressType.LONG
+
     def __repr__(self):
         return "Message(type={})".format(MessageType(self.type).name)
 
@@ -369,12 +372,15 @@ class MessagesSet(object):
 
         return message
 
-    def next_mle_message(self, command_type, assert_enabled=True):
+    def next_mle_message(self, command_type, assert_enabled=True, sent_to_node=None):
         message = self.next_mle_message_of_one_of_command_types(command_type)
 
         if assert_enabled:
             assert message is not None, "Could not find MleMessage of the type: {}".format(command_type)
 
+        if sent_to_node != None:
+            message.assertSentToNode(sent_to_node)
+
         return message
 
     def next_mle_message_of_one_of_command_types(self, *command_types):
@@ -399,6 +405,34 @@ class MessagesSet(object):
 
         return message
 
+    def next_message(self, assert_enabled=True):
+        message = self.messages.pop(0)
+        if assert_enabled:
+            assert message is not None, "Could not find next Message"
+        return message
+
+    def next_message_of(self, message_type, assert_enabled=True):
+        message = None
+
+        while self.messages:
+            m = self.messages.pop(0)
+            if m.type != message_type:
+                continue
+
+            message = m
+            break
+
+        if assert_enabled:
+            assert message is not None, "Could not find Message of the type: {}".format(message_type)
+
+        return message
+
+    def next_data_message(self):
+        return self.next_message_of(MessageType.DATA)
+
+    def next_command_message(self):
+        return self.next_message_of(MessageType.COMMAND)
+
     def contains_icmp_message(self):
         for m in self.messages:
             if m.type == MessageType.ICMP: