Stabilize git driver tests

These tests relied on sleeps which can cause races when running
the full test suite in parallel.  Instead, wait for the events
we know will happen to happen.

Also remove the dependency on yarl now that aiohttp has made a
release which works with yarl 1.0 (however, it does not work with
<1.0 which is why this needs to be combined with this change to
fix tests).

Change-Id: Ib1c626cdd3f083dd1d23a3c6547bd7163b66567e

3 files changed, 33 insertions, 16 deletions

diff --git a/requirements.txt b/requirements.txt
index 193c64e71..39a2b0268 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -25,6 +25,5 @@ cryptography>=1.6
 cachecontrol
 pyjwt
 iso8601
-yarl>=0.11,<1.0
 aiohttp
 uvloop;python_version>='3.5'
diff --git a/tests/unit/test_git_driver.py b/tests/unit/test_git_driver.py
index b9e6c6e92..e8762d0d2 100644
--- a/tests/unit/test_git_driver.py
+++ b/tests/unit/test_git_driver.py
@@ -24,6 +24,11 @@ class TestGitDriver(ZuulTestCase):
     config_file = 'zuul-git-driver.conf'
     tenant_config_file = 'config/git-driver/main.yaml'
 
+    def setUp(self):
+        super(TestGitDriver, self).setUp()
+        self.git_connection = self.sched.connections.getSource('git').\
+            connection
+
     def setup_config(self):
         super(TestGitDriver, self).setup_config()
         self.config.set('connection git', 'baseurl', self.upstream_root)
@@ -70,8 +75,8 @@ class TestGitDriver(ZuulTestCase):
         self.addCommitToRepo(
             'common-config', 'Change zuul.yaml configuration', files)
 
-        # Let some time for the tenant reconfiguration to happen
-        time.sleep(2)
+        # Wait for the tenant reconfiguration to happen
+        count = self.waitForEvent()
         self.waitUntilSettled()
 
         A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
@@ -109,8 +114,8 @@ class TestGitDriver(ZuulTestCase):
         # Restart the git watcher
         self.sched.connections.getSource('git').connection.w_pause = False
 
-        # Let some time for the tenant reconfiguration to happen
-        time.sleep(2)
+        # Wait for the tenant reconfiguration to happen
+        self.waitForEvent(count)
         self.waitUntilSettled()
 
         A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A')
@@ -123,23 +128,33 @@ class TestGitDriver(ZuulTestCase):
 
     def ensure_watcher_has_context(self):
         # Make sure watcher have read initial refs shas
-        cnx = self.sched.connections.getSource('git').connection
         delay = 0.1
         max_delay = 1
-        while not cnx.projects_refs:
+        while not self.git_connection.projects_refs:
             time.sleep(delay)
             max_delay -= delay
             if max_delay <= 0:
                 raise Exception("Timeout waiting for initial read")
+        return self.git_connection.watcher_thread._event_count
+
+    def waitForEvent(self, initial_count=0):
+        delay = 0.1
+        max_delay = 1
+        while self.git_connection.watcher_thread._event_count <= initial_count:
+            time.sleep(delay)
+            max_delay -= delay
+            if max_delay <= 0:
+                raise Exception("Timeout waiting for event")
+        return self.git_connection.watcher_thread._event_count
 
     @simple_layout('layouts/basic-git.yaml', driver='git')
     def test_ref_updated_event(self):
-        self.ensure_watcher_has_context()
+        count = self.ensure_watcher_has_context()
         # Add a commit to trigger a ref-updated event
         self.addCommitToRepo(
             'org/project', 'A change for ref-updated', {'f1': 'Content'})
-        # Let some time for the git watcher to detect the ref-update event
-        time.sleep(0.2)
+        # Wait for the git watcher to detect the ref-update event
+        self.waitForEvent(count)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
         self.assertEqual('SUCCESS',
@@ -147,12 +162,12 @@ class TestGitDriver(ZuulTestCase):
 
     @simple_layout('layouts/basic-git.yaml', driver='git')
     def test_ref_created(self):
-        self.ensure_watcher_has_context()
+        count = self.ensure_watcher_has_context()
         # Tag HEAD to trigger a ref-updated event
         self.addTagToRepo(
             'org/project', 'atag', 'HEAD')
-        # Let some time for the git watcher to detect the ref-update event
-        time.sleep(0.2)
+        # Wait for the git watcher to detect the ref-update event
+        self.waitForEvent(count)
         self.waitUntilSettled()
         self.assertEqual(len(self.history), 1)
         self.assertEqual('SUCCESS',
@@ -160,12 +175,12 @@ class TestGitDriver(ZuulTestCase):
 
     @simple_layout('layouts/basic-git.yaml', driver='git')
     def test_ref_deleted(self):
-        self.ensure_watcher_has_context()
+        count = self.ensure_watcher_has_context()
         # Delete default tag init to trigger a ref-updated event
         self.delTagFromRepo(
             'org/project', 'init')
-        # Let some time for the git watcher to detect the ref-update event
-        time.sleep(0.2)
+        # Wait for the git watcher to detect the ref-update event
+        self.waitForEvent(count)
         self.waitUntilSettled()
         # Make sure no job as run as ignore-delete is True by default
         self.assertEqual(len(self.history), 0)
diff --git a/zuul/driver/git/gitconnection.py b/zuul/driver/git/gitconnection.py
index 03b24cadc..1886cfcca 100644
--- a/zuul/driver/git/gitconnection.py
+++ b/zuul/driver/git/gitconnection.py
@@ -38,6 +38,8 @@ class GitWatcher(threading.Thread):
         self.poll_delay = poll_delay
         self._stopped = False
         self.projects_refs = self.git_connection.projects_refs
+        # This is used by the test framework
+        self._event_count = 0
 
     def compareRefs(self, project, refs):
         partial_events = []
@@ -112,6 +114,7 @@ class GitWatcher(threading.Thread):
                     self.git_connection.logEvent(event)
                     # Pass the event to the scheduler
                     self.git_connection.sched.addEvent(event)
+                    self._event_count += 1
         except Exception as e:
             self.log.debug("Unexpected issue in _run loop: %s" % str(e))