diff --git a/tracker/test/webcomponentspage_test.py b/tracker/test/webcomponentspage_test.py
new file mode 100644
index 0000000..65cfc66
--- /dev/null
+++ b/tracker/test/webcomponentspage_test.py
@@ -0,0 +1,120 @@
+# Copyright 2020 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 or at
+# https://developers.google.com/open-source/licenses/bsd
+"""Tests for the Monorail SPA pages, as served by EZT."""
+from __future__ import print_function
+from __future__ import division
+from __future__ import absolute_import
+
+import mock
+import unittest
+
+import ezt
+
+import settings
+from framework import permissions
+from proto import project_pb2
+from proto import site_pb2
+from services import service_manager
+from tracker import webcomponentspage
+from testing import fake
+from testing import testing_helpers
+
+
+class WebComponentsPageTest(unittest.TestCase):
+
+  def setUp(self):
+    self.services = service_manager.Services(
+        user=fake.UserService(),
+        project=fake.ProjectService(),
+        features=fake.FeaturesService())
+
+    self.user = self.services.user.TestAddUser('user@example.com', 111)
+    self.project = self.services.project.TestAddProject('proj', project_id=789)
+    self.hotlist = self.services.features.TestAddHotlist(
+        'HotlistName', summary='summary', owner_ids=[111], hotlist_id=1236)
+
+    self.servlet = webcomponentspage.WebComponentsPage(
+        'req', 'res', services=self.services)
+
+  def testHotlistPage_OldUiUrl(self):
+    mr = testing_helpers.MakeMonorailRequest(
+        user_info={'user_id': 111},
+        path='/hotlists/1236',
+        services=self.services)
+
+    page_data = self.servlet.GatherPageData(mr)
+    self.assertEqual('/u/111/hotlists/HotlistName', page_data['old_ui_url'])
+
+  def testHotlistPage_OldUiUrl_People(self):
+    mr = testing_helpers.MakeMonorailRequest(
+        user_info={'user_id': 111},
+        path='/hotlists/1236/people',
+        services=self.services)
+
+    page_data = self.servlet.GatherPageData(mr)
+    self.assertEqual(
+        '/u/111/hotlists/HotlistName/people', page_data['old_ui_url'])
+
+  def testHotlistPage_OldUiUrl_Settings(self):
+    mr = testing_helpers.MakeMonorailRequest(
+        user_info={'user_id': 111},
+        path='/hotlists/1236/settings',
+        services=self.services)
+
+    page_data = self.servlet.GatherPageData(mr)
+    self.assertEqual(
+        '/u/111/hotlists/HotlistName/details', page_data['old_ui_url'])
+
+
+class ProjectListPageTest(unittest.TestCase):
+
+  def setUp(self):
+    self.services = service_manager.Services(project=fake.ProjectService())
+
+    self.project_a = self.services.project.TestAddProject('a', project_id=1)
+    self.project_b = self.services.project.TestAddProject('b', project_id=2)
+
+    self.servlet = webcomponentspage.ProjectListPage(
+        'req', 'res', services=self.services)
+
+  @mock.patch('settings.domain_to_default_project', {})
+  def testMaybeRedirectToDomainDefaultProject_NoMatch(self):
+    """No redirect if the user is not accessing via a configured domain."""
+    mr = testing_helpers.MakeMonorailRequest()
+    mr.request.host = 'example.com'
+    msg = self.servlet._MaybeRedirectToDomainDefaultProject(mr)
+    print('msg: ' + msg)
+    self.assertTrue(msg.startswith('No configured'))
+
+  @mock.patch('settings.domain_to_default_project', {'example.com': 'huh'})
+  def testMaybeRedirectToDomainDefaultProject_NoSuchProject(self):
+    """No redirect if the configured project does not exist."""
+    mr = testing_helpers.MakeMonorailRequest()
+    mr.request.host = 'example.com'
+    print('host is %r' % mr.request.host)
+    msg = self.servlet._MaybeRedirectToDomainDefaultProject(mr)
+    print('msg: ' + msg)
+    self.assertTrue(msg.endswith('not found'))
+
+  @mock.patch('settings.domain_to_default_project', {'example.com': 'a'})
+  def testMaybeRedirectToDomainDefaultProject_CantView(self):
+    """No redirect if the user can't view the configured project."""
+    self.project_a.access = project_pb2.ProjectAccess.MEMBERS_ONLY
+    mr = testing_helpers.MakeMonorailRequest()
+    mr.request.host = 'example.com'
+    msg = self.servlet._MaybeRedirectToDomainDefaultProject(mr)
+    print('msg: ' + msg)
+    self.assertTrue(msg.startswith('User cannot'))
+
+  @mock.patch('settings.domain_to_default_project', {'example.com': 'a'})
+  def testMaybeRedirectToDomainDefaultProject_Redirect(self):
+    """We redirect if there's a configured project that the user can view."""
+    mr = testing_helpers.MakeMonorailRequest()
+    mr.request.host = 'example.com'
+    self.servlet.redirect = mock.Mock()
+    msg = self.servlet._MaybeRedirectToDomainDefaultProject(mr)
+    print('msg: ' + msg)
+    self.assertTrue(msg.startswith('Redirected'))
+    self.servlet.redirect.assert_called_once()