Proper errors when server cannot bind

sanic/server.py

@@ -151,7 +151,14 @@ def serve(host, port, request_handler, after_start=None, before_stop=None, debug
         request_timeout=request_timeout,
         request_max_size=request_max_size,
     ), host, port)
-    http_server = loop.run_until_complete(server_coroutine)
+    try:
+        http_server = loop.run_until_complete(server_coroutine)
+    except OSError as e:
+        log.error("Unable to start server: {}".format(e))
+        return
+    except:
+        log.exception("Unable to start server")
+        return
 
     # Run the on_start function if provided
     if after_start:

tests/performance/sanic/simple_server.py

@@ -18,4 +18,4 @@ async def test(request):
 async def test(request):
     return json({ "test": True, "files": request.files, "fields": request.form })
 
-app.run(host="0.0.0.0", port=sys.argv[1], debug=True)
+app.run(host="0.0.0.0", port=sys.argv[1])