diff --git a/features/test/pubsub_test.py b/features/test/pubsub_test.py
new file mode 100644
index 0000000..2044cf7
--- /dev/null
+++ b/features/test/pubsub_test.py
@@ -0,0 +1,110 @@
+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is govered by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""Tests for features.pubsub."""
+
+from __future__ import print_function
+from __future__ import division
+from __future__ import absolute_import
+
+import unittest
+
+from mock import Mock
+
+from features import pubsub
+from services import service_manager
+from testing import fake
+from testing import testing_helpers
+
+
+class PublishPubsubIssueChangeTaskTest(unittest.TestCase):
+
+  def setUp(self):
+    self.services = service_manager.Services(
+        user=fake.UserService(),
+        project=fake.ProjectService(),
+        config=fake.ConfigService(),
+        issue=fake.IssueService(),
+        features=fake.FeaturesService())
+    self.services.project.TestAddProject(
+        'test-project', owner_ids=[1, 3],
+        project_id=12345)
+
+    # Stub the pubsub API (there is no pubsub testbed stub).
+    self.pubsub_client_mock = Mock()
+    pubsub.set_up_pubsub_api = Mock(return_value=self.pubsub_client_mock)
+
+  def testPublishPubsubIssueChangeTask_NoIssueIdParam(self):
+    """Test case when issue_id param is not passed."""
+    task = pubsub.PublishPubsubIssueChangeTask(
+        request=None, response=None, services=self.services)
+    mr = testing_helpers.MakeMonorailRequest(
+        user_info={'user_id': 1},
+        params={},
+        method='POST',
+        services=self.services)
+    result = task.HandleRequest(mr)
+    expected_body = {
+      'error': 'Cannot proceed without a valid issue ID.',
+    }
+    self.assertEqual(result, expected_body)
+
+  def testPublishPubsubIssueChangeTask_PubSubAPIInitFailure(self):
+    """Test case when pub/sub API fails to init."""
+    pubsub.set_up_pubsub_api = Mock(return_value=None)
+    task = pubsub.PublishPubsubIssueChangeTask(
+        request=None, response=None, services=self.services)
+    mr = testing_helpers.MakeMonorailRequest(
+        user_info={'user_id': 1},
+        params={},
+        method='POST',
+        services=self.services)
+    result = task.HandleRequest(mr)
+    expected_body = {
+      'error': 'Pub/Sub API init failure.',
+    }
+    self.assertEqual(result, expected_body)
+
+  def testPublishPubsubIssueChangeTask_IssueNotFound(self):
+    """Test case when issue is not found."""
+    task = pubsub.PublishPubsubIssueChangeTask(
+        request=None, response=None, services=self.services)
+    mr = testing_helpers.MakeMonorailRequest(
+        user_info={'user_id': 1},
+        params={'issue_id': 314159},
+        method='POST',
+        services=self.services)
+    result = task.HandleRequest(mr)
+    expected_body = {
+      'error': 'Could not find issue with ID 314159',
+    }
+    self.assertEqual(result, expected_body)
+
+  def testPublishPubsubIssueChangeTask_Normal(self):
+    """Test normal happy-path case."""
+    issue = fake.MakeTestIssue(789, 543, 'sum', 'New', 111, issue_id=78901,
+        project_name='rutabaga')
+    self.services.issue.TestAddIssue(issue)
+    task = pubsub.PublishPubsubIssueChangeTask(
+        request=None, response=None, services=self.services)
+    mr = testing_helpers.MakeMonorailRequest(
+        user_info={'user_id': 1},
+        params={'issue_id': 78901},
+        method='POST',
+        services=self.services)
+    result = task.HandleRequest(mr)
+
+    self.pubsub_client_mock.projects().topics().publish.assert_called_once_with(
+      topic='projects/testing-app/topics/issue-updates',
+      body={
+        'messages': [{
+          'attributes': {
+            'local_id': '543',
+            'project_name': 'rutabaga',
+          },
+        }],
+      }
+    )
+    self.assertEqual(result, {})