Add support for build category in BuildEvent

infra_libs/event_mon/test/monitoring_test.py

Index: infra_libs/event_mon/test/monitoring_test.py
diff --git a/infra_libs/event_mon/test/monitoring_test.py b/infra_libs/event_mon/test/monitoring_test.py
index 055122ba5c2314b093dc27c360fc5118630b9257..51316be2fa9c9f5180fb9b4cd1bec924bbd3ad22 100644
--- a/infra_libs/event_mon/test/monitoring_test.py
+++ b/infra_libs/event_mon/test/monitoring_test.py
@@ -328,6 +328,35 @@ class GetBuildEventTest(unittest.TestCase):
         'BUILD', 'bot.host.name', 'build_name', bbucket_id='foo').log_event()
     self.assertIsInstance(log_event, LogRequestLite.LogEventLite)
 
+  def test_get_build_event_with_category(self):
+    log_event = monitoring.get_build_event(
+        'BUILD', 'bot.host.name', 'build_name',
+        category='git_cl_try').log_event()
+    self.assertIsInstance(log_event, LogRequestLite.LogEventLite)
+
+    # Check that source_extension deserializes to the right thing.
+    event = ChromeInfraEvent.FromString(log_event.source_extension)
+    self.assertTrue(event.HasField('build_event'))
+    self.assertEquals(
+        event.build_event.category, BuildEvent.CATEGORY_GIT_CL_TRY)
+
+    # Try unknown value. Should produce CATEGORY_UNKNOWN.
+    log_event = monitoring.get_build_event(
+        'BUILD', 'bot.host.name', 'build_name', category='foobar').log_event()
+    self.assertIsInstance(log_event, LogRequestLite.LogEventLite)
+    event = ChromeInfraEvent.FromString(log_event.source_extension)
+    self.assertTrue(event.HasField('build_event'))
+    self.assertEquals(
+        event.build_event.category, BuildEvent.CATEGORY_UNKNOWN)
+
+    # Try empty value. Should not set category.
+    log_event = monitoring.get_build_event(
+        'BUILD', 'bot.host.name', 'build_name', category='').log_event()
+    self.assertIsInstance(log_event, LogRequestLite.LogEventLite)
+    event = ChromeInfraEvent.FromString(log_event.source_extension)
+    self.assertTrue(event.HasField('build_event'))
+    self.assertFalse(event.build_event.HasField('category'))
+
   def test_get_build_event_invalid_type(self):
     # An invalid type is a critical error.
     log_event = monitoring.get_build_event('INVALID_TYPE',