Properly deregister polling hook when there's no models to poll

app/mixins/polling.coffee

@@ -48,15 +48,13 @@ mixin = Ember.Mixin.create
     @get('polling').startPollingHook(this) if @pollHook
 
   stopPolling: ->
-    pollModels = @get('pollModels')
-    return unless pollModels
+    if pollModels = @get('pollModels') 
+      pollModels = [pollModels] unless Ember.isArray(pollModels)
 
-    pollModels = [pollModels] unless Ember.isArray(pollModels)
-
-    pollModels.forEach (property) =>
-      @stopPollingModel(property)
-      @removeObserver(property, this, 'pollModelDidChange')
-      Ember.removeBeforeObserver(this, property, this, 'pollModelWillChange')
+      pollModels.forEach (property) =>
+        @stopPollingModel(property)
+        @removeObserver(property, this, 'pollModelDidChange')
+        Ember.removeBeforeObserver(this, property, this, 'pollModelWillChange')
 
     @get('polling').stopPollingHook(this)
 

tests/unit/mixins/polling-test.coffee

@@ -47,6 +47,21 @@ moduleForComponent 'polling-test', 'PollingTestComponent', {
     pollingChangesHistory = []
 }
 
+test 'it properly stops polling hook without any models', ->
+  component = @subject(pollModels: null)
+  @append()
+
+  Ember.run ->
+    component.destroy()
+
+  expected = [
+    { type: 'start-hook', source: '<PollingTestingComponent>' },
+    { type: 'stop-hook', source: '<PollingTestingComponent>' }
+  ]
+
+  deepEqual pollingChangesHistory, expected
+
+
 test 'it works even if one of the model is null', ->
   component = @subject(model1: { name: 'model1' })
   @append()