diff --git a/tests/unit/test_executor.py b/tests/unit/test_executor.py
index 7b76802..4700bd1 100755
--- a/tests/unit/test_executor.py
+++ b/tests/unit/test_executor.py
@@ -248,6 +248,46 @@
 
         self.assertBuildStates(states, projects)
 
+    def test_periodic_override(self):
+        # This test can not use simple_layout because it must start
+        # with a configuration which does not include a
+        # timer-triggered job so that we have an opportunity to set
+        # the hold flag before the first job.
+
+        # This tests that we can override the branch in a timer
+        # trigger (mostly to ensure backwards compatability for jobs).
+        self.executor_server.hold_jobs_in_build = True
+        # Start timer trigger - also org/project
+        self.commitConfigUpdate('common-config',
+                                'layouts/repo-checkout-timer-override.yaml')
+        self.sched.reconfigure(self.config)
+
+        p1 = 'review.example.com/org/project1'
+        projects = [p1]
+        self.create_branch('org/project1', 'stable/havana')
+
+        # The pipeline triggers every second, so we should have seen
+        # several by now.
+        time.sleep(5)
+        self.waitUntilSettled()
+
+        # Stop queuing timer triggered jobs so that the assertions
+        # below don't race against more jobs being queued.
+        self.commitConfigUpdate('common-config',
+                                'layouts/repo-checkout-no-timer.yaml')
+        self.sched.reconfigure(self.config)
+
+        self.assertEquals(1, len(self.builds), "One build is running")
+
+        upstream = self.getUpstreamRepos(projects)
+        states = [
+            {p1: dict(commit=str(upstream[p1].commit('stable/havana')),
+                      branch='stable/havana'),
+             },
+        ]
+
+        self.assertBuildStates(states, projects)
+
     def test_periodic(self):
         # This test can not use simple_layout because it must start
         # with a configuration which does not include a
@@ -274,14 +314,19 @@
                                 'layouts/repo-checkout-no-timer.yaml')
         self.sched.reconfigure(self.config)
 
-        self.assertEquals(1, len(self.builds), "One build is running")
+        self.assertEquals(2, len(self.builds), "Two builds are running")
 
         upstream = self.getUpstreamRepos(projects)
         states = [
             {p1: dict(commit=str(upstream[p1].commit('stable/havana')),
                       branch='stable/havana'),
              },
+            {p1: dict(commit=str(upstream[p1].commit('master')),
+                      branch='master'),
+             },
         ]
+        if self.builds[0].parameters['zuul']['ref'] == 'refs/heads/master':
+            states = list(reversed(states))
 
         self.assertBuildStates(states, projects)
 
diff --git a/tests/unit/test_github_driver.py b/tests/unit/test_github_driver.py
index 0cfe3da..8493570 100644
--- a/tests/unit/test_github_driver.py
+++ b/tests/unit/test_github_driver.py
@@ -12,11 +12,14 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import os
 import re
 from testtools.matchers import MatchesRegex, StartsWith
 import urllib
 import time
 
+import git
+
 from tests.base import ZuulTestCase, simple_layout, random_sha1
 
 
@@ -94,7 +97,16 @@
     def test_tag_event(self):
         self.executor_server.hold_jobs_in_build = True
 
-        sha = random_sha1()
+        self.create_branch('org/project', 'tagbranch')
+        files = {'README.txt': 'test'}
+        self.addCommitToRepo('org/project', 'test tag',
+                             files, branch='tagbranch', tag='newtag')
+        path = os.path.join(self.upstream_root, 'org/project')
+        repo = git.Repo(path)
+        tag = repo.tags['newtag']
+        sha = tag.commit.hexsha
+        del repo
+
         self.fake_github.emitEvent(
             self.fake_github.getPushEvent('org/project', 'refs/tags/newtag',
                                           new_rev=sha))
diff --git a/tests/unit/test_scheduler.py b/tests/unit/test_scheduler.py
index d9cf839..3e60ead 100755
--- a/tests/unit/test_scheduler.py
+++ b/tests/unit/test_scheduler.py
@@ -1806,17 +1806,17 @@
         self.commitConfigUpdate('common-config', 'layouts/no-timer.yaml')
         self.sched.reconfigure(self.config)
 
-        self.assertEqual(len(self.builds), 2, "Two timer jobs")
+        self.assertEqual(len(self.builds), 1, "One timer job")
 
         A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
         self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
         self.waitUntilSettled()
-        self.assertEqual(len(self.builds), 3, "One change plus two timer jobs")
+        self.assertEqual(len(self.builds), 2, "One change plus one timer job")
 
         self.fake_gerrit.addEvent(A.getChangeAbandonedEvent())
         self.waitUntilSettled()
 
-        self.assertEqual(len(self.builds), 2, "Two timer jobs remain")
+        self.assertEqual(len(self.builds), 1, "One timer job remains")
 
         self.executor_server.release()
         self.waitUntilSettled()
@@ -2777,6 +2777,7 @@
         # with a configuration which does not include a
         # timer-triggered job so that we have an opportunity to set
         # the hold flag before the first job.
+        self.create_branch('org/project', 'stable')
         self.executor_server.hold_jobs_in_build = True
         self.commitConfigUpdate('common-config', 'layouts/timer.yaml')
         self.sched.reconfigure(self.config)
@@ -2803,10 +2804,12 @@
         self.executor_server.release()
         self.waitUntilSettled()
 
-        self.assertEqual(self.getJobFromHistory(
-            'project-bitrot-stable-old').result, 'SUCCESS')
-        self.assertEqual(self.getJobFromHistory(
-            'project-bitrot-stable-older').result, 'SUCCESS')
+        self.assertHistory([
+            dict(name='project-bitrot', result='SUCCESS',
+                 ref='refs/heads/master'),
+            dict(name='project-bitrot', result='SUCCESS',
+                 ref='refs/heads/stable'),
+        ], ordered=False)
 
         data = json.loads(data)
         status_jobs = set()
@@ -2816,8 +2819,7 @@
                     for change in head:
                         for job in change['jobs']:
                             status_jobs.add(job['name'])
-        self.assertIn('project-bitrot-stable-old', status_jobs)
-        self.assertIn('project-bitrot-stable-older', status_jobs)
+        self.assertIn('project-bitrot', status_jobs)
 
     def test_idle(self):
         "Test that frequent periodic jobs work"
@@ -2846,12 +2848,12 @@
                                     'layouts/no-timer.yaml')
             self.sched.reconfigure(self.config)
             self.waitUntilSettled()
-            self.assertEqual(len(self.builds), 2,
+            self.assertEqual(len(self.builds), 1,
                              'Timer builds iteration #%d' % x)
             self.executor_server.release('.*')
             self.waitUntilSettled()
             self.assertEqual(len(self.builds), 0)
-            self.assertEqual(len(self.history), x * 2)
+            self.assertEqual(len(self.history), x)
 
     @simple_layout('layouts/smtp.yaml')
     def test_check_smtp_pool(self):
diff --git a/tests/unit/test_v3.py b/tests/unit/test_v3.py
index 734c45c..9c7ffea 100644
--- a/tests/unit/test_v3.py
+++ b/tests/unit/test_v3.py
@@ -667,7 +667,8 @@
         self.assertFalse(os.path.exists(pre_flag_path))
         post_flag_path = os.path.join(self.test_root, build.uuid +
                                       '.post.flag')
-        self.assertTrue(os.path.exists(post_flag_path))
+        self.assertTrue(os.path.exists(post_flag_path),
+                        "The file %s should exist" % post_flag_path)
 
 
 class TestBrokenConfig(ZuulTestCase):