add ability to override default host in blueprint

sanic/blueprints.py

@@ -87,18 +87,18 @@ class Blueprint:
         for deferred in self.deferred_functions:
             deferred(state)
 
-    def route(self, uri, methods=None):
+    def route(self, uri, methods=None, host=None):
         """
         """
         def decorator(handler):
-            self.record(lambda s: s.add_route(handler, uri, methods))
+            self.record(lambda s: s.add_route(handler, uri, methods, host))
             return handler
         return decorator
 
-    def add_route(self, handler, uri, methods=None):
+    def add_route(self, handler, uri, methods=None, host=None):
         """
         """
-        self.record(lambda s: s.add_route(handler, uri, methods))
+        self.record(lambda s: s.add_route(handler, uri, methods, host))
         return handler
 
     def listener(self, event):

tests/test_blueprints.py

@@ -67,13 +67,22 @@ def test_bp_with_host():
     def handler(request):
         return text('Hello')
 
+    @bp.route('/', host="sub.example.com")
+    def handler(request):
+        return text('Hello subdomain!')
+
     app.blueprint(bp)
     headers = {"Host": "example.com"}
     request, response = sanic_endpoint_test(app, uri='/test1/',
                                             headers=headers)
-
     assert response.text == 'Hello'
 
+    headers = {"Host": "sub.example.com"}
+    request, response = sanic_endpoint_test(app, uri='/test1/',
+                                            headers=headers)
+
+    assert response.text == 'Hello subdomain!'
+
 
 def test_several_bp_with_host():
     app = Sanic('test_text')