test(cluster): add test for handling frames

The tests ensure that:
1. A cluster specific response is sent even when disable default response is set.
2. A default response is not sent when disable default response is set.
3. A default response is not sent in response to receiving a default response.
4. A default response is not sent in response to a group addressed frame.
5. A default response (error status) is sent when the frame could not be handled by the resp. cluster.

lib/Endpoint.js

@@ -104,10 +104,7 @@ class Endpoint extends EventEmitter {
    */
   async handleFrame(clusterId, frame, meta) {
     const rawFrame = frame;
-
-    if (rawFrame[0] & 0x4) {
-      frame = ZCLMfgSpecificHeader.fromBuffer(rawFrame);
-    } else frame = ZCLStandardHeader.fromBuffer(rawFrame);
+    frame = Endpoint.parseFrame(frame);
 
     // NOTE: we do not respond with a default response if:
     // 1. The frame we received is a default response (frame.cmdId = 11)
@@ -194,6 +191,13 @@ class Endpoint extends EventEmitter {
     return result;
   }
 
+  static parseFrame(frame) {
+    if (frame[0] & 0x4) {
+      return ZCLMfgSpecificHeader.fromBuffer(frame);
+    }
+    return ZCLStandardHeader.fromBuffer(frame);
+  }
+
 }
 
 module.exports = Endpoint;