Fix wildcard support

Author: Laurent Papier

nmqtt.nim

@@ -839,6 +839,10 @@ proc onPublish(ctx: MqttCtx, pkt: Pkt) {.async.} =
       if top == topic or top == "#":
         cb.cb(topic, message)
       if top.endsWith("/#"):
+        # the multi-level wildcard can represent zero levels.
+        if topic == top[0 .. ^3]:
+          cb.cb(topic, message)
+          continue
         var topicw = top
         topicw.removeSuffix("#")
         if topic.contains(topicw):

tests/subscribe.nim

@@ -201,11 +201,12 @@ suite "test suite for subscribe":
       await sleepAsync 500
       await ctxMain.publish("test/random1", msg, 0)
       await ctxMain.publish("second/random2", msg, 0)
+      await ctxMain.publish("test", msg, 0)
       await ctxMain.publish("test/random3", msg, 0)
       await sleepAsync 500
       await ctxListen.unsubscribe("test/#")
       await sleepAsync 500
-      check(msgCount == 2)
+      check(msgCount == 3)
 
     waitFor conn()