[Telemetry] Add API for updating ts_proxy_server's traffic settings

telemetry/telemetry/internal/util/ts_proxy_server_unittest.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import unittest
 
 from telemetry.internal.util import ts_proxy_server
 
 class TsProxyServerTest(unittest.TestCase):
   def testParseTsProxyPort(self):
@@ skipping 14 matching lines @@
     with ts_proxy_server.TsProxyServer() as server:
       self.assertIsNotNone(server.port)
     with ts_proxy_server.TsProxyServer(None, 37124, 37125) as server:
       self.assertIsNotNone(server.port)
 
   def testSmokeUpdatingOutboundPorts(self):
     with ts_proxy_server.TsProxyServer() as server:
       self.assertIsNotNone(server.port)
       server.UpdateOutboundPorts(31242, 14220)
 
-  def testSmokeUpdatingOutboundPortsInvalid(self):
+  def testSmokeUpdateOutboundPortsInvalid(self):
     with ts_proxy_server.TsProxyServer() as server:
       self.assertIsNotNone(server.port)
       with self.assertRaises(AssertionError):
         server.UpdateOutboundPorts(31242, 'abcde')
+
+  def testSmokeUpdateTrafficSettings(self):
+    with ts_proxy_server.TsProxyServer() as server:
+      server.UpdateTrafficSettings(round_trip_latency_ms=100)
+      server.UpdateTrafficSettings(download_bandwidth_kbps=5000)
+      server.UpdateTrafficSettings(upload_bandwidth_kbps=2000)
+      server.UpdateTrafficSettings(
+          round_trip_latency_ms=200, download_bandwidth_kbps=500,
+          upload_bandwidth_kbps=2000)