Update metrics.proto, and set metric descriptions in MetricsData messages

infra_libs/ts_mon/common/test/metrics_test.py

 # Copyright 2015 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 sys
 import textwrap
 import unittest
 
 import mock
 from infra_libs.ts_mon.protos import metrics_pb2
@@ skipping 35 matching lines @@
     self.assertEquals(len(e.exception.fields), 8)
 
   def test_serialize(self):
     t = targets.DeviceTarget('reg', 'role', 'net', 'host')
     m = metrics.StringMetric('test')
     m.set('val')
     p = metrics_pb2.MetricsCollection()
     m.serialize_to(p, 1234, (('bar', 1), ('baz', False)), m.get(), t)
     return str(p).splitlines()
 
+  def test_serialize_with_description(self):
+    t = targets.DeviceTarget('reg', 'role', 'net', 'host')
+    m = metrics.StringMetric('test', description='a custom description')
+    m.set('val')
+    p = metrics_pb2.MetricsCollection()
+    m.serialize_to(p, 1234, (('bar', 1), ('baz', False)), m.get(), t)
+    return str(p).splitlines()
+
   def test_serialize_too_many_fields(self):
     m = metrics.StringMetric('test', fields={'a': 1, 'b': 2, 'c': 3, 'd': 4})
     m.set('val', fields={'e': 5, 'f': 6, 'g': 7})
     with self.assertRaises(errors.MonitoringTooManyFieldsError):
       m.set('val', fields={'e': 5, 'f': 6, 'g': 7, 'h': 8})
 
   def test_populate_field_values(self):
     pb1 = metrics_pb2.MetricsData()
     m1 = metrics.Metric('foo', fields={'asdf': 1})
     m1._populate_fields(pb1, m1._normalized_fields)
@@ skipping 431 matching lines @@
     m.add(25)
     p = metrics_pb2.MetricsCollection()
     m.serialize_to(p, 1234, (), m.get(), t)
     self.assertEquals(1234000000, p.data[0].start_timestamp_us)
 
   def test_is_cumulative(self):
     cd = metrics.CumulativeDistributionMetric('test')
     ncd = metrics.NonCumulativeDistributionMetric('test2')
     self.assertTrue(cd.is_cumulative())
     self.assertFalse(ncd.is_cumulative())