ensure delivery count is set correctly on drain

lib/link.js

@@ -354,6 +354,7 @@ Receiver.prototype.on_flow = function (frame) {
     this.dispatch('receiver_flow', this._context());
     if (frame.performative.drain) {
         this.credit = frame.performative.link_credit;
+        this.delivery_count = frame.performative.delivery_count;
         if (frame.performative.link_credit > 0) console.error('ERROR: received flow with drain set, but non zero credit');
         else this.dispatch('receiver_drained', this._context());
     }

package.json

@@ -1,6 +1,6 @@
 {
     "name": "rhea",
-    "version": "0.3.10",
+    "version": "0.3.11",
     "description": "reactive AMQP 1.0 library",
     "homepage": "http://github.com/amqp/rhea",
     "license": "Apache-2.0",

test/links.ts

@@ -791,4 +791,54 @@ describe('miscellaneous', function() {
             done();
         });
     });
+
+    it('handles drain correctly', function(done: Function) {
+        var queue = [] as any;
+        var sender: any;
+        server.on('sender_open', function (context: rhea.EventContext) {
+            sender = context.sender!;
+        });
+        server.on('sender_draining', function (context: rhea.EventContext) {
+            context.sender!.set_drained(queue.length === 0);
+        });
+        server.on('receiver_open', function (context: rhea.EventContext) {
+            context.receiver!.add_credit(100);
+        });
+        server.on('message', function (context: rhea.EventContext) {
+            queue.push(context.message!.body);
+            while (sender.sendable && queue.length) {
+                sender.send({body:queue.shift()});
+            }
+        });
+        server.on('sendable', function (context: rhea.EventContext) {
+            while (context.sender!.sendable && queue.length) {
+                context.sender!.send({body:queue.shift()});
+            }
+        });
+        var conn = client.connect(listener.address() as any);
+        var received: string;
+        var r = conn.open_receiver({credit_window:0}) as any;
+        var s = conn.open_sender() as any;
+        r.on('message', function (context: rhea.EventContext) {
+            received = context.message!.body;
+            r.close();
+        });
+        r.once('receiver_drained', function () {
+            s.send({body:'post-drain'});
+        });
+        r.drain = true;
+        r.flow(1);
+        s.on('accepted', function () {
+            r.drain = true;
+            r.flow(1);
+        });
+        client.on('receiver_close', function (context: rhea.EventContext) {
+            context.connection.close();
+        });
+        client.on('connection_close', function (context: rhea.EventContext) {
+            assert.deepEqual(received, 'post-drain');
+            done();
+        });
+    });
+
 });