tests: support generating longer publish packets

Remaining length for publish packets wasn't being handled completely.

Signed-off-by: Karl Palsson <karlp@etactica.com>

test/mosq_test.py

@@ -306,7 +306,7 @@ def gen_connack(resv=0, rc=0):
 
 def gen_publish(topic, qos, payload=None, retain=False, dup=False, mid=0):
     rl = 2+len(topic)
-    pack_format = "!BBH"+str(len(topic))+"s"
+    pack_format = "H"+str(len(topic))+"s"
     if qos > 0:
         rl = rl + 2
         pack_format = pack_format + "H"
@@ -317,6 +317,7 @@ def gen_publish(topic, qos, payload=None, retain=False, dup=False, mid=0):
         payload = ""
         pack_format = pack_format + "0s"
 
+    rlpacked = pack_remaining_length(rl)
     cmd = 48 | (qos<<1)
     if retain:
         cmd = cmd + 1
@@ -324,9 +325,9 @@ def gen_publish(topic, qos, payload=None, retain=False, dup=False, mid=0):
         cmd = cmd + 8
 
     if qos > 0:
-        return struct.pack(pack_format, cmd, rl, len(topic), topic, mid, payload)
+        return struct.pack("!B" + str(len(rlpacked))+"s" + pack_format, cmd, rlpacked, len(topic), topic, mid, payload)
     else:
-        return struct.pack(pack_format, cmd, rl, len(topic), topic, payload)
+        return struct.pack("!B" + str(len(rlpacked))+"s" + pack_format, cmd, rlpacked, len(topic), topic, payload)
 
 def gen_puback(mid):
     return struct.pack('!BBH', 64, 2, mid)