From ca941ff4321d5b9b356bff14942bbd004bf846f2 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Fri, 5 Jul 2019 13:50:58 -0400
Subject: [PATCH 01/23] Begin

---
 .github/main.workflow         | 44 +++++++++++++++++++++--------------
 .taskcluster.yml              |  4 ++--
 tools/ci/update_pr_preview.py | 40 +++++++++++++++++++++++++++++++
 3 files changed, 69 insertions(+), 19 deletions(-)
 create mode 100644 tools/ci/update_pr_preview.py

diff --git a/.github/main.workflow b/.github/main.workflow
index 4f4447fdf0..dd6773f508 100644
--- a/.github/main.workflow
+++ b/.github/main.workflow
@@ -1,21 +1,31 @@
-workflow "Build & Release Manifest" {
-  on = "push"
-  resolves = ["manifest-build-and-tag"]
-}
+#workflow "Build & Release Manifest" {
+#  on = "push"
+#  resolves = ["manifest-build-and-tag"]
+#}
+#
+#action "manifest-build-and-tag" {
+#  uses = "./tools/docker/github"
+#  runs = ["python", "tools/ci/manifest_build.py"]
+#  secrets = ["GITHUB_TOKEN"]
+#}
+#
+#workflow "Build & Publish Documentation Website" {
+#  on = "push"
+#  resolves = ["website-build-and-publish"]
+#}
+#
+#action "website-build-and-publish" {
+#  uses = "./tools/docker/documentation"
+#  runs = ["/bin/bash", "tools/ci/website_build.sh"]
+#  secrets = ["DEPLOY_TOKEN"]
+#}
 
-action "manifest-build-and-tag" {
-  uses = "./tools/docker/github"
-  runs = ["python", "tools/ci/manifest_build.py"]
-  secrets = ["GITHUB_TOKEN"]
+workflow "Synchronize the Pull Request Preview" {
+  on = "pull_request"
+  resolves = "update-pr-preview"
 }
 
-workflow "Build & Publish Documentation Website" {
-  on = "push"
-  resolves = ["website-build-and-publish"]
-}
-
-action "website-build-and-publish" {
-  uses = "./tools/docker/documentation"
-  runs = ["/bin/bash", "tools/ci/website_build.sh"]
-  secrets = ["DEPLOY_TOKEN"]
+action "update-pr-preview" {
+  uses = "./tools/docker/github"
+  runs = ["python", "tools/ci/update_pr_preview.py"]
 }
diff --git a/.taskcluster.yml b/.taskcluster.yml
index a8e297242f..e069c1702b 100644
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -6,7 +6,7 @@ tasks:
     event_str: {$json: {$eval: event}}
   in:
     $flattenDeep:
-      - $if: tasks_for == "github-push"
+      - $if: false
         then:
           $map:
             $flatten:
@@ -100,7 +100,7 @@ tasks:
                         --test-type=${chunk[0]}
                         --this-chunk=${chunk[1]}
                         --total-chunks=${chunk[2]};
-      - $if: tasks_for == "github-pull-request"
+      - $if: false
         # PR tasks that run the tests in various configurations
         then:
           # Taskcluster responds to a number of events issued by the GitHub API
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
new file mode 100644
index 0000000000..9978be3d2f
--- /dev/null
+++ b/tools/ci/update_pr_preview.py
@@ -0,0 +1,40 @@
+import json
+import logging
+import os
+import subprocess
+import sys
+
+import requests
+
+here = os.path.abspath(os.path.dirname(__file__))
+wpt_root = os.path.abspath(os.path.join(here, os.pardir, os.pardir))
+
+if not(wpt_root in sys.path):
+    sys.path.append(wpt_root)
+
+from tools.wpt.testfiles import get_git_cmd
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+class Status(object):
+    SUCCESS = 0
+    FAIL = 1
+    NEUTRAL = 78
+
+
+def main():
+    owner, repo = os.environ['GITHUB_REPOSITORY'].split('/', 1)
+
+    with open(os.environ['GITHUB_EVENT_PATH']) as f:
+        event = json.load(f)
+        logger.info(json.dumps(event, indent=2))
+
+    return Status.SUCCESS
+
+
+if __name__ == '__main__':
+    code = main()
+    assert isinstance(code, int)
+    sys.exit(code)

From 7ac7bcc4e3a531da749a0449aaf8b113ddc41662 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Fri, 5 Jul 2019 20:44:01 -0400
Subject: [PATCH 02/23] Complete initial implementation

---
 .github/main.workflow                    |   2 +-
 tools/ci/tests/test_update_pr_preview.py | 277 +++++++++++++++++++++++
 tools/ci/update_pr_preview.py            | 183 ++++++++++++++-
 tools/tox.ini                            |   2 +
 4 files changed, 458 insertions(+), 6 deletions(-)
 create mode 100644 tools/ci/tests/test_update_pr_preview.py

diff --git a/.github/main.workflow b/.github/main.workflow
index dd6773f508..02949638f7 100644
--- a/.github/main.workflow
+++ b/.github/main.workflow
@@ -27,5 +27,5 @@ workflow "Synchronize the Pull Request Preview" {
 
 action "update-pr-preview" {
   uses = "./tools/docker/github"
-  runs = ["python", "tools/ci/update_pr_preview.py"]
+  runs = ["python", "tools/ci/update_pr_preview.py", "https://api.github.com"]
 }
diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
new file mode 100644
index 0000000000..7c766ed6df
--- /dev/null
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -0,0 +1,277 @@
+import BaseHTTPServer
+import json
+import os
+import pytest
+import subprocess
+import tempfile
+import threading
+
+subject = os.path.join(
+    os.path.dirname(os.path.abspath(__file__)), '..', 'update_pr_preview.py'
+)
+test_host = 'localhost'
+
+
+class TestHandler(BaseHTTPServer.BaseHTTPRequestHandler, object):
+    def do_all(self):
+        request = (self.command, self.path)
+        self.server.requests.append(request)
+        self.send_response(self.server.responses.get(request, 200))
+        self.end_headers()
+        self.wfile.write('{}')
+    def do_DELETE(self):
+        return self.do_all()
+    def do_GET(self):
+        return self.do_all()
+    def do_PATCH(self):
+        return self.do_all()
+    def do_POST(self):
+        return self.do_all()
+
+
+class TestServer(BaseHTTPServer.HTTPServer, object):
+    '''This server responds to all HTTP requests with status code 200 unless an
+    alternative status code is specified for the given method and path in the
+    `responses` parameter.'''
+    def __init__(self, address, responses=None):
+        super(TestServer, self).__init__(address, TestHandler)
+        self.responses = responses or {}
+        self.requests = []
+
+
+def assert_success(returncode):
+    assert returncode == 0
+
+
+def assert_neutral(returncode):
+    assert returncode == 78
+
+
+def assert_fail(returncode):
+    assert returncode not in (0, 78)
+
+
+def run(event_data, responses=None):
+    event_data_file = tempfile.mkstemp()[1]
+    env = {
+        'GITHUB_EVENT_PATH': event_data_file,
+        'GITHUB_REPOSITORY': 'test-org/test-repo'
+    }
+    env.update(os.environ)
+    server = TestServer((test_host, 0), responses)
+    test_port = server.server_address[1]
+    threading.Thread(target=lambda: server.serve_forever()).start()
+
+    try:
+        with open(event_data_file, 'w') as handle:
+            json.dump(event_data, handle)
+
+        child = subprocess.Popen(
+            ['python', subject, 'http://{}:{}'.format(test_host, test_port)],
+            env=env
+        )
+
+        child.communicate()
+    finally:
+        server.shutdown()
+        os.remove(event_data_file)
+
+    return child.returncode, server.requests
+
+
+def default_data(action):
+    return {
+        'pull_request': {
+            'number': 543,
+            'closed_at': None,
+            'head': {
+                'sha': 'deadbeef'
+            },
+            'user': {
+                'login': 'rms'
+            },
+            'labels': [
+               { 'name': 'foo' },
+               { 'name': 'bar' }
+            ]
+        },
+        'action': action
+    }
+
+
+
+def test_close_active_with_label():
+    event_data = default_data('close')
+    event_data['pull_request']['closed_at'] = '2019-07-05'
+    event_data['pull_request']['labels'].append(
+        {'name': 'pull-request-has-preview'}
+    )
+    expected = (
+        'DELETE',
+        '/repos/test-org/test-repo/issues/543/labels/pull-request-has-preview'
+    )
+
+    returncode, requests = run(event_data)
+
+    assert_success(returncode)
+    assert expected in requests
+
+
+def test_close_active_with_label_error():
+    event_data = default_data('close')
+    event_data['pull_request']['closed_at'] = '2019-07-05'
+    event_data['pull_request']['labels'].append(
+        {'name': 'pull-request-has-preview'}
+    )
+    responses = {(
+        'DELETE',
+        '/repos/test-org/test-repo/issues/543/labels/pull-request-has-preview'
+    ): 500}
+
+    returncode, requests = run(event_data, responses)
+
+    assert_fail(returncode)
+
+
+def test_close_active_without_label():
+    event_data = default_data('close')
+    event_data['pull_request']['closed_at'] = '2019-07-05'
+
+    returncode, requests = run(event_data)
+
+    assert_neutral(returncode)
+    assert len(requests) == 0
+
+
+def test_open_with_label():
+    event_data = default_data('open')
+    event_data['pull_request']['labels'].append(
+        {'name': 'pull-request-has-preview'}
+    )
+
+    returncode, requests = run(event_data)
+
+    assert_success(returncode)
+    expected = (
+        'PATCH',
+        '/repos/test-org/test-repo/git/refs/pr_preview_543'
+    )
+    assert expected in requests
+
+
+def test_open_without_label_for_collaborator():
+    event_data = default_data('open')
+
+    returncode, requests = run(event_data)
+
+    assert_success(returncode)
+    check_collaborator = (
+        'GET', '/repos/test-org/test-repo/collaborators/rms'
+    )
+    create_label = (
+        'POST',
+        '/repos/test-org/test-repo/issues/543/labels'
+    )
+    assert len(requests) == 2
+    assert check_collaborator in requests
+    assert create_label in requests
+
+
+def test_open_without_label_for_non_collaborator():
+    event_data = default_data('open')
+    responses = {
+        ('GET', '/repos/test-org/test-repo/collaborators/rms'): 404
+    }
+
+    returncode, requests = run(event_data, responses)
+
+    assert_neutral(returncode)
+    expected = [(
+        'GET', '/repos/test-org/test-repo/collaborators/rms'
+    )]
+    assert expected == requests
+
+
+def test_add_unrelated_label():
+    event_data = default_data('label')
+    event_data['label'] = {'name': 'foobar'}
+    event_data['pull_request']['labels'].append({'name': 'foobar'})
+
+    returncode, requests = run(event_data)
+
+    assert_neutral(returncode)
+    assert len(requests) == 0
+
+
+def test_add_active_label():
+    event_data = default_data('label')
+    event_data['label'] = {'name': 'pull-request-has-preview'}
+    event_data['pull_request']['labels'].append(
+        {'name': 'pull-request-has-preview'}
+    )
+
+    returncode, requests = run(event_data)
+
+    assert_success(returncode)
+    expected = (
+        'PATCH',
+        '/repos/test-org/test-repo/git/refs/pr_preview_543'
+    )
+    assert expected in requests
+
+
+def test_remove_unrelated_label():
+    event_data = default_data('unlabel')
+    event_data['label'] = {'name': 'foobar'}
+
+    returncode, requests = run(event_data)
+
+    assert_neutral(returncode)
+    assert len(requests) == 0
+
+
+def test_remove_active_label():
+    event_data = default_data('unlabel')
+    event_data['label'] = {'name': 'pull-request-has-preview'}
+    expected = ('DELETE', '/repos/test-org/test-repo/git/refs/pr_preview_543')
+
+    returncode, requests = run(event_data)
+
+    assert_success(returncode)
+    assert expected in requests
+
+
+def test_synchronize_without_label():
+    event_data = default_data('synchronize')
+
+    returncode, requests = run(event_data)
+
+    assert_neutral(returncode)
+    assert len(requests) == 0
+
+
+def test_synchronize_with_label():
+    event_data = default_data('synchronize')
+    event_data['pull_request']['labels'].append(
+        {'name': 'pull-request-has-preview'}
+    )
+
+    returncode, requests = run(event_data)
+
+    assert_success(returncode)
+    expected = (
+        'PATCH',
+        '/repos/test-org/test-repo/git/refs/pr_preview_543'
+    )
+    assert expected in requests
+
+
+def test_unrecognized_action():
+    event_data = default_data('assigned')
+
+    returncode, requests = run(event_data)
+
+    assert_neutral(returncode)
+    assert len(requests) == 0
+
+
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 9978be3d2f..3a7d5a70d4 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -8,6 +8,7 @@
 
 here = os.path.abspath(os.path.dirname(__file__))
 wpt_root = os.path.abspath(os.path.join(here, os.pardir, os.pardir))
+active_label = 'pull-request-has-preview'
 
 if not(wpt_root in sys.path):
     sys.path.append(wpt_root)
@@ -24,17 +25,189 @@ class Status(object):
     NEUTRAL = 78
 
 
-def main():
-    owner, repo = os.environ['GITHUB_REPOSITORY'].split('/', 1)
+def request(url, method_name, data=None, json_data=None, params=None,
+            extra_headers=None):
+    github_token = os.environ.get('GITHUB_TOKEN')
+    headers = {
+        'Authorization': 'token {}'.format(github_token),
+        'Accept': 'application/vnd.github.machine-man-preview+json'
+    }
+
+    if extra_headers is not None:
+        headers.update(extra_headers)
+
+    kwargs = {
+        'params': params,
+        'headers': headers
+    }
+    method = getattr(requests, method_name)
+
+    logger.info('Loading URL %s' % url)
+    if json_data is not None or data is not None:
+        kwargs['json'] = json_data
+        kwargs['data'] = data
+
+    resp = method(url, **kwargs)
+
+    resp.raise_for_status()
+
+    return resp.json()
+
+
+def resource_exists(url):
+    try:
+        request(url, 'get')
+    except requests.HTTPError as exception:
+        if exception.response.status_code == 404:
+            return False
+        raise
+
+    return True
+
+
+class GitHub(object):
+    def __init__(self, api_root, owner, repo):
+        self.api_root = api_root
+        self.owner = owner
+        self.repo = repo
+
+    def is_collaborator(self, login):
+        return resource_exists(
+            '{}/repos/{}/{}/collaborators/{}'.format(
+                self.api_root, self.owner, self.repo, login
+            )
+        )
+
+    def tag_exists(self, tag):
+        return resource_exists(
+            '{}/repos/{}/{}/git/refs/{}'.format(
+                self.api_root, self.owner, self.repo, tag
+            )
+        )
+
+    def create_tag(self, tag, sha):
+        data = {
+            'ref': 'refs/tags/{}'.format(tag),
+            'sha': sha
+        }
+        url = '{}/repos/{}/{}/git/refs'.format(
+            self.api_root, self.owner, self.repo
+        )
+
+        request(url, 'post', json_data=data)
+
+    def update_tag(self, tag, sha):
+        data = {
+            'force': True,
+            'sha': sha
+        }
+        url = '{}/repos/{}/{}/git/refs/{}'.format(
+            self.api_root, self.owner, self.repo, tag
+        )
+
+        request(url, 'patch', json_data=data)
 
-    with open(os.environ['GITHUB_EVENT_PATH']) as f:
-        event = json.load(f)
+    def delete_tag(self, tag):
+        url = '{}/repos/{}/{}/git/refs/{}'.format(
+            self.api_root, self.owner, self.repo, tag
+        )
+
+        try:
+            request(url, 'delete')
+        except requests.HTTPError as exception:
+            if exception.response.status_code != 404:
+                raise
+
+            logger.info(
+                'Attempted to delete non-existent tag: {}'.format(tag_name)
+            )
+
+    def tag(self, tag, sha):
+        if self.tag_exists(tag):
+            self.update_tag(tag, sha)
+        else:
+            self.create_tag(tag, sha)
+
+        logger.info('Tagged {} as {}'.format(sha, tag))
+
+    def add_label(self, pr_number, label_name):
+        data = {
+            'labels': [label_name]
+        }
+        url = '{}/repos/{}/{}/issues/{}/labels'.format(
+            self.api_root, self.owner, self.repo, pr_number
+        )
+
+        request(url, 'post', json_data=data)
+
+    def remove_label(self, pr_number, label_name):
+        url = '{}/repos/{}/{}/issues/{}/labels/{}'.format(
+            self.api_root, self.owner, self.repo, pr_number, label_name
+        )
+
+        try:
+            request(url, 'delete')
+        except requests.HTTPError as exception:
+            if exception.response.status_code != 404:
+                raise
+
+            logger.info(
+                'Attempted to delete non-existent tag: {}'.format(tag_name)
+            )
+
+
+def main(api_root):
+    with open(os.environ['GITHUB_EVENT_PATH']) as handle:
+        event = json.load(handle)
         logger.info(json.dumps(event, indent=2))
 
+    if 'pull_request' not in event:
+        logger.info('Unexpected event data')
+        return Status.FAIL
+
+    owner, repo = os.environ['GITHUB_REPOSITORY'].split('/', 1)
+    github = GitHub(api_root, owner, repo)
+    action = event['action']
+    pr_number = event['pull_request']['number']
+    tag_name = 'pr_preview_{}'.format(pr_number)
+    sha = event['pull_request']['head']['sha']
+    is_open = event['pull_request']['closed_at'] is None
+    login = event['pull_request']['user']['login']
+    has_label = any(
+        [label['name'] == active_label
+        for label in event['pull_request']['labels']]
+    )
+    target_label = event.get('label', {}).get('name')
+
+
+    if not is_open:
+        if action == 'close' and has_label:
+            # This operation will trigger another GitHub Action which will
+            # subsequently delete the tag.
+            github.remove_label(pr_number, active_label)
+            return Status.SUCCESS
+
+        return Status.NEUTRAL
+
+    if action in ('open', 'reopen') and has_label:
+        github.tag(tag_name, sha)
+    elif action in ('open', 'reopen') and github.is_collaborator(login):
+        # This operation will trigger another GitHub Action which will
+        # subsequently create the tag.
+        github.add_label(pr_number, active_label)
+    elif action == 'label' and target_label == active_label:
+        github.tag(tag_name, sha)
+    elif action == 'unlabel' and target_label == active_label:
+        github.delete_tag(tag_name)
+    elif action == 'synchronize' and has_label:
+        github.tag(tag_name, sha)
+    else:
+        return Status.NEUTRAL
+
     return Status.SUCCESS
 
 
 if __name__ == '__main__':
-    code = main()
+    code = main(sys.argv[1])
     assert isinstance(code, int)
     sys.exit(code)
diff --git a/tools/tox.ini b/tools/tox.ini
index ba6dc038a1..aba4f3faaa 100644
--- a/tools/tox.ini
+++ b/tools/tox.ini
@@ -8,6 +8,8 @@ deps =
   pytest-cov
   mock
   hypothesis
+  # `requests` is required by `update_pr_preview.py`
+  requests
 
 commands = pytest {posargs}
 

From cdbf8338ce50904ea796ea748ed00f7437eed877 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 10:50:41 -0400
Subject: [PATCH 03/23] Correct linting infractions

---
 tools/ci/tests/test_update_pr_preview.py | 13 +++++++------
 tools/ci/update_pr_preview.py            | 12 ++----------
 2 files changed, 9 insertions(+), 16 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index 7c766ed6df..6a8d59cedc 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -1,7 +1,6 @@
 import BaseHTTPServer
 import json
 import os
-import pytest
 import subprocess
 import tempfile
 import threading
@@ -19,18 +18,22 @@ def do_all(self):
         self.send_response(self.server.responses.get(request, 200))
         self.end_headers()
         self.wfile.write('{}')
+
     def do_DELETE(self):
         return self.do_all()
+
     def do_GET(self):
         return self.do_all()
+
     def do_PATCH(self):
         return self.do_all()
+
     def do_POST(self):
         return self.do_all()
 
 
 class TestServer(BaseHTTPServer.HTTPServer, object):
-    '''This server responds to all HTTP requests with status code 200 unless an
+    '''HTTP server that responds to all requests with status code 200 unless an
     alternative status code is specified for the given method and path in the
     `responses` parameter.'''
     def __init__(self, address, responses=None):
@@ -91,8 +94,8 @@ def default_data(action):
                 'login': 'rms'
             },
             'labels': [
-               { 'name': 'foo' },
-               { 'name': 'bar' }
+                {'name': 'foo'},
+                {'name': 'bar'}
             ]
         },
         'action': action
@@ -273,5 +276,3 @@ def test_unrecognized_action():
 
     assert_neutral(returncode)
     assert len(requests) == 0
-
-
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 3a7d5a70d4..deac6cd575 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -1,20 +1,12 @@
 import json
 import logging
 import os
-import subprocess
 import sys
 
 import requests
 
-here = os.path.abspath(os.path.dirname(__file__))
-wpt_root = os.path.abspath(os.path.join(here, os.pardir, os.pardir))
 active_label = 'pull-request-has-preview'
 
-if not(wpt_root in sys.path):
-    sys.path.append(wpt_root)
-
-from tools.wpt.testfiles import get_git_cmd
-
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
@@ -119,7 +111,7 @@ def delete_tag(self, tag):
                 raise
 
             logger.info(
-                'Attempted to delete non-existent tag: {}'.format(tag_name)
+                'Attempted to delete non-existent tag: {}'.format(tag)
             )
 
     def tag(self, tag, sha):
@@ -152,7 +144,7 @@ def remove_label(self, pr_number, label_name):
                 raise
 
             logger.info(
-                'Attempted to delete non-existent tag: {}'.format(tag_name)
+                'Attempted to remove non-existent label: {}'.format(label_name)
             )
 
 

From 37b2c112f63df447353860efcd7431f693043140 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 13:44:23 -0400
Subject: [PATCH 04/23] Add some documentation

---
 docs/writing-tests/submission-process.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/docs/writing-tests/submission-process.md b/docs/writing-tests/submission-process.md
index d6ddce5a76..2a0aa0c47b 100644
--- a/docs/writing-tests/submission-process.md
+++ b/docs/writing-tests/submission-process.md
@@ -38,6 +38,23 @@ Hop on to the [mailing list][public-test-infra] or [IRC][]
 no need to announce your review request, as soon as you make a Pull Request
 GitHub will inform interested parties.
 
+## Previews
+
+The website [wpt-submissions.live](http://wpt-submissions.live) exists to help
+contributors demonstrate their proposed changes to others. If your pull request
+is open and has the GitHub label `pull-request-has-preview`, then it will be
+available at `http://wpt-submissions.live/{{pull request ID}}`, where "pull
+request ID" is the numeric identifier for the pull request.
+
+For example, a pull request at https://github.com/web-platform-tests/wpt/pull/3
+has a pull request ID `3`. Once that has been assigned the
+`pull-request-has-preview` label, then its contents can be viewed at
+http://wpt-submissions.live/3.
+
+If you are [a GitHub
+collaborator](https://help.github.com/en/articles/permission-levels-for-a-user-account-repository)
+on WPT, the label and the preview will be created automatically.
+
 [repo]: https://github.com/web-platform-tests/wpt/
 [github flow]: https://guides.github.com/introduction/flow/
 [public-test-infra]: https://lists.w3.org/Archives/Public/public-test-infra/

From ee2d3f9fe0966df6910383fb9e827b0ae385bb8b Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 13:51:02 -0400
Subject: [PATCH 05/23] Add logging

---
 tools/ci/update_pr_preview.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index deac6cd575..b9548b8b23 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -86,6 +86,8 @@ def create_tag(self, tag, sha):
             self.api_root, self.owner, self.repo
         )
 
+        logger.info('Creating tag "{}" as {}'.format(tag, sha))
+
         request(url, 'post', json_data=data)
 
     def update_tag(self, tag, sha):
@@ -97,6 +99,8 @@ def update_tag(self, tag, sha):
             self.api_root, self.owner, self.repo, tag
         )
 
+        logger.info('Updating tag "{}" as {}'.format(tag, sha))
+
         request(url, 'patch', json_data=data)
 
     def delete_tag(self, tag):
@@ -104,6 +108,8 @@ def delete_tag(self, tag):
             self.api_root, self.owner, self.repo, tag
         )
 
+        logger.info('Deleting tag "{}" as {}'.format(tag, sha))
+
         try:
             request(url, 'delete')
         except requests.HTTPError as exception:
@@ -120,8 +126,6 @@ def tag(self, tag, sha):
         else:
             self.create_tag(tag, sha)
 
-        logger.info('Tagged {} as {}'.format(sha, tag))
-
     def add_label(self, pr_number, label_name):
         data = {
             'labels': [label_name]
@@ -130,6 +134,8 @@ def add_label(self, pr_number, label_name):
             self.api_root, self.owner, self.repo, pr_number
         )
 
+        logger.info('Adding label')
+
         request(url, 'post', json_data=data)
 
     def remove_label(self, pr_number, label_name):
@@ -137,6 +143,8 @@ def remove_label(self, pr_number, label_name):
             self.api_root, self.owner, self.repo, pr_number, label_name
         )
 
+        logger.info('Removing label')
+
         try:
             request(url, 'delete')
         except requests.HTTPError as exception:

From 314208ec8eb9e2831b8b34daac828e66a88360f8 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 13:56:38 -0400
Subject: [PATCH 06/23] Authorize action

---
 .github/main.workflow | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/main.workflow b/.github/main.workflow
index 02949638f7..4b076bb4c6 100644
--- a/.github/main.workflow
+++ b/.github/main.workflow
@@ -28,4 +28,5 @@ workflow "Synchronize the Pull Request Preview" {
 action "update-pr-preview" {
   uses = "./tools/docker/github"
   runs = ["python", "tools/ci/update_pr_preview.py", "https://api.github.com"]
+  secrets = ["GITHUB_TOKEN"]
 }

From c8fa1c1f35dce91f21b46cab49c290665bdae5ed Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 14:09:11 -0400
Subject: [PATCH 07/23] Removed referenced to undefined variable

---
 tools/ci/update_pr_preview.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index b9548b8b23..3e97ca4d87 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -108,7 +108,7 @@ def delete_tag(self, tag):
             self.api_root, self.owner, self.repo, tag
         )
 
-        logger.info('Deleting tag "{}" as {}'.format(tag, sha))
+        logger.info('Deleting tag "{}"'.format(tag))
 
         try:
             request(url, 'delete')

From ca74abc4b43b2ae00d7cc5da95c222fcbd9465e2 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 14:09:28 -0400
Subject: [PATCH 08/23] Correct API references

---
 tools/ci/tests/test_update_pr_preview.py | 10 ++++++----
 tools/ci/update_pr_preview.py            |  6 +++---
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index 6a8d59cedc..e1f1eaa6fb 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -157,7 +157,7 @@ def test_open_with_label():
     assert_success(returncode)
     expected = (
         'PATCH',
-        '/repos/test-org/test-repo/git/refs/pr_preview_543'
+        '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
     )
     assert expected in requests
 
@@ -218,7 +218,7 @@ def test_add_active_label():
     assert_success(returncode)
     expected = (
         'PATCH',
-        '/repos/test-org/test-repo/git/refs/pr_preview_543'
+        '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
     )
     assert expected in requests
 
@@ -236,7 +236,9 @@ def test_remove_unrelated_label():
 def test_remove_active_label():
     event_data = default_data('unlabel')
     event_data['label'] = {'name': 'pull-request-has-preview'}
-    expected = ('DELETE', '/repos/test-org/test-repo/git/refs/pr_preview_543')
+    expected = (
+        'DELETE', '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
+    )
 
     returncode, requests = run(event_data)
 
@@ -264,7 +266,7 @@ def test_synchronize_with_label():
     assert_success(returncode)
     expected = (
         'PATCH',
-        '/repos/test-org/test-repo/git/refs/pr_preview_543'
+        '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
     )
     assert expected in requests
 
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 3e97ca4d87..48b429000c 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -72,7 +72,7 @@ def is_collaborator(self, login):
 
     def tag_exists(self, tag):
         return resource_exists(
-            '{}/repos/{}/{}/git/refs/{}'.format(
+            '{}/repos/{}/{}/git/refs/tags/{}'.format(
                 self.api_root, self.owner, self.repo, tag
             )
         )
@@ -95,7 +95,7 @@ def update_tag(self, tag, sha):
             'force': True,
             'sha': sha
         }
-        url = '{}/repos/{}/{}/git/refs/{}'.format(
+        url = '{}/repos/{}/{}/git/refs/tags/{}'.format(
             self.api_root, self.owner, self.repo, tag
         )
 
@@ -104,7 +104,7 @@ def update_tag(self, tag, sha):
         request(url, 'patch', json_data=data)
 
     def delete_tag(self, tag):
-        url = '{}/repos/{}/{}/git/refs/{}'.format(
+        url = '{}/repos/{}/{}/git/refs/tags/{}'.format(
             self.api_root, self.owner, self.repo, tag
         )
 

From 8bb8bd40d0e475479b7947b90854db53bb9adc1c Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 14:20:21 -0400
Subject: [PATCH 09/23] Correct action names

---
 tools/ci/tests/test_update_pr_preview.py | 20 ++++++++++----------
 tools/ci/update_pr_preview.py            | 10 +++++-----
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index e1f1eaa6fb..57813197fa 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -104,7 +104,7 @@ def default_data(action):
 
 
 def test_close_active_with_label():
-    event_data = default_data('close')
+    event_data = default_data('closed')
     event_data['pull_request']['closed_at'] = '2019-07-05'
     event_data['pull_request']['labels'].append(
         {'name': 'pull-request-has-preview'}
@@ -121,7 +121,7 @@ def test_close_active_with_label():
 
 
 def test_close_active_with_label_error():
-    event_data = default_data('close')
+    event_data = default_data('closed')
     event_data['pull_request']['closed_at'] = '2019-07-05'
     event_data['pull_request']['labels'].append(
         {'name': 'pull-request-has-preview'}
@@ -137,7 +137,7 @@ def test_close_active_with_label_error():
 
 
 def test_close_active_without_label():
-    event_data = default_data('close')
+    event_data = default_data('closed')
     event_data['pull_request']['closed_at'] = '2019-07-05'
 
     returncode, requests = run(event_data)
@@ -147,7 +147,7 @@ def test_close_active_without_label():
 
 
 def test_open_with_label():
-    event_data = default_data('open')
+    event_data = default_data('opened')
     event_data['pull_request']['labels'].append(
         {'name': 'pull-request-has-preview'}
     )
@@ -163,7 +163,7 @@ def test_open_with_label():
 
 
 def test_open_without_label_for_collaborator():
-    event_data = default_data('open')
+    event_data = default_data('opened')
 
     returncode, requests = run(event_data)
 
@@ -181,7 +181,7 @@ def test_open_without_label_for_collaborator():
 
 
 def test_open_without_label_for_non_collaborator():
-    event_data = default_data('open')
+    event_data = default_data('opened')
     responses = {
         ('GET', '/repos/test-org/test-repo/collaborators/rms'): 404
     }
@@ -196,7 +196,7 @@ def test_open_without_label_for_non_collaborator():
 
 
 def test_add_unrelated_label():
-    event_data = default_data('label')
+    event_data = default_data('labeled')
     event_data['label'] = {'name': 'foobar'}
     event_data['pull_request']['labels'].append({'name': 'foobar'})
 
@@ -207,7 +207,7 @@ def test_add_unrelated_label():
 
 
 def test_add_active_label():
-    event_data = default_data('label')
+    event_data = default_data('labeled')
     event_data['label'] = {'name': 'pull-request-has-preview'}
     event_data['pull_request']['labels'].append(
         {'name': 'pull-request-has-preview'}
@@ -224,7 +224,7 @@ def test_add_active_label():
 
 
 def test_remove_unrelated_label():
-    event_data = default_data('unlabel')
+    event_data = default_data('unlabeled')
     event_data['label'] = {'name': 'foobar'}
 
     returncode, requests = run(event_data)
@@ -234,7 +234,7 @@ def test_remove_unrelated_label():
 
 
 def test_remove_active_label():
-    event_data = default_data('unlabel')
+    event_data = default_data('unlabeled')
     event_data['label'] = {'name': 'pull-request-has-preview'}
     expected = (
         'DELETE', '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 48b429000c..3548a9eff9 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -181,7 +181,7 @@ def main(api_root):
 
 
     if not is_open:
-        if action == 'close' and has_label:
+        if action == 'closed' and has_label:
             # This operation will trigger another GitHub Action which will
             # subsequently delete the tag.
             github.remove_label(pr_number, active_label)
@@ -189,15 +189,15 @@ def main(api_root):
 
         return Status.NEUTRAL
 
-    if action in ('open', 'reopen') and has_label:
+    if action in ('opened', 'reopened') and has_label:
         github.tag(tag_name, sha)
-    elif action in ('open', 'reopen') and github.is_collaborator(login):
+    elif action in ('opened', 'reopened') and github.is_collaborator(login):
         # This operation will trigger another GitHub Action which will
         # subsequently create the tag.
         github.add_label(pr_number, active_label)
-    elif action == 'label' and target_label == active_label:
+    elif action == 'labeled' and target_label == active_label:
         github.tag(tag_name, sha)
-    elif action == 'unlabel' and target_label == active_label:
+    elif action == 'unlabeled' and target_label == active_label:
         github.delete_tag(tag_name)
     elif action == 'synchronize' and has_label:
         github.tag(tag_name, sha)

From c36351523e1fed6118cbd259bfd22a57ec4621d5 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 14:41:16 -0400
Subject: [PATCH 10/23] Ignore response body for existence checks

---
 tools/ci/tests/test_update_pr_preview.py | 20 ++++++++++++--------
 tools/ci/update_pr_preview.py            |  7 ++++---
 2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index 57813197fa..8529e8fdde 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -15,9 +15,10 @@ class TestHandler(BaseHTTPServer.BaseHTTPRequestHandler, object):
     def do_all(self):
         request = (self.command, self.path)
         self.server.requests.append(request)
-        self.send_response(self.server.responses.get(request, 200))
+        status_code, body = self.server.responses.get(request, (200, '{}'))
+        self.send_response(status_code)
         self.end_headers()
-        self.wfile.write('{}')
+        self.wfile.write(body)
 
     def do_DELETE(self):
         return self.do_all()
@@ -33,9 +34,9 @@ def do_POST(self):
 
 
 class TestServer(BaseHTTPServer.HTTPServer, object):
-    '''HTTP server that responds to all requests with status code 200 unless an
-    alternative status code is specified for the given method and path in the
-    `responses` parameter.'''
+    '''HTTP server that responds to all requests with status code 200 and body
+    '{}' unless an alternative status code and body are specified for the given
+    method and path in the `responses` parameter.'''
     def __init__(self, address, responses=None):
         super(TestServer, self).__init__(address, TestHandler)
         self.responses = responses or {}
@@ -129,7 +130,7 @@ def test_close_active_with_label_error():
     responses = {(
         'DELETE',
         '/repos/test-org/test-repo/issues/543/labels/pull-request-has-preview'
-    ): 500}
+    ): (500, '{}')}
 
     returncode, requests = run(event_data, responses)
 
@@ -164,8 +165,11 @@ def test_open_with_label():
 
 def test_open_without_label_for_collaborator():
     event_data = default_data('opened')
+    responses = {
+        ('GET', '/repos/test-org/test-repo/collaborators/rms'): (204, '')
+    }
 
-    returncode, requests = run(event_data)
+    returncode, requests = run(event_data, responses)
 
     assert_success(returncode)
     check_collaborator = (
@@ -183,7 +187,7 @@ def test_open_without_label_for_collaborator():
 def test_open_without_label_for_non_collaborator():
     event_data = default_data('opened')
     responses = {
-        ('GET', '/repos/test-org/test-repo/collaborators/rms'): 404
+        ('GET', '/repos/test-org/test-repo/collaborators/rms'): (404, '{}')
     }
 
     returncode, requests = run(event_data, responses)
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 3548a9eff9..a97ed7745d 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -18,7 +18,7 @@ class Status(object):
 
 
 def request(url, method_name, data=None, json_data=None, params=None,
-            extra_headers=None):
+            extra_headers=None, ignore_body=False):
     github_token = os.environ.get('GITHUB_TOKEN')
     headers = {
         'Authorization': 'token {}'.format(github_token),
@@ -43,12 +43,13 @@ def request(url, method_name, data=None, json_data=None, params=None,
 
     resp.raise_for_status()
 
-    return resp.json()
+    if not ignore_body:
+        return resp.json()
 
 
 def resource_exists(url):
     try:
-        request(url, 'get')
+        request(url, 'get', ignore_body=True)
     except requests.HTTPError as exception:
         if exception.response.status_code == 404:
             return False

From 20d35430c86063d2f94d57a0b51a9b93ac7464c5 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 15:39:16 -0400
Subject: [PATCH 11/23] Improve class names

---
 tools/ci/tests/test_update_pr_preview.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index 8529e8fdde..e699f029d8 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -11,7 +11,7 @@
 test_host = 'localhost'
 
 
-class TestHandler(BaseHTTPServer.BaseHTTPRequestHandler, object):
+class MockHandler(BaseHTTPServer.BaseHTTPRequestHandler, object):
     def do_all(self):
         request = (self.command, self.path)
         self.server.requests.append(request)
@@ -33,12 +33,12 @@ def do_POST(self):
         return self.do_all()
 
 
-class TestServer(BaseHTTPServer.HTTPServer, object):
+class MockServer(BaseHTTPServer.HTTPServer, object):
     '''HTTP server that responds to all requests with status code 200 and body
     '{}' unless an alternative status code and body are specified for the given
     method and path in the `responses` parameter.'''
     def __init__(self, address, responses=None):
-        super(TestServer, self).__init__(address, TestHandler)
+        super(MockServer, self).__init__(address, MockHandler)
         self.responses = responses or {}
         self.requests = []
 
@@ -62,7 +62,7 @@ def run(event_data, responses=None):
         'GITHUB_REPOSITORY': 'test-org/test-repo'
     }
     env.update(os.environ)
-    server = TestServer((test_host, 0), responses)
+    server = MockServer((test_host, 0), responses)
     test_port = server.server_address[1]
     threading.Thread(target=lambda: server.serve_forever()).start()
 

From 0a3094c5c658b5c6730d6d0e977a5985ba350542 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 15:45:59 -0400
Subject: [PATCH 12/23] Omit body in response to DELETE requests

---
 tools/ci/tests/test_update_pr_preview.py | 11 ++++++-----
 tools/ci/update_pr_preview.py            |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index e699f029d8..06aa83df0b 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -240,14 +240,15 @@ def test_remove_unrelated_label():
 def test_remove_active_label():
     event_data = default_data('unlabeled')
     event_data['label'] = {'name': 'pull-request-has-preview'}
-    expected = (
-        'DELETE', '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
-    )
+    responses = {
+        ('DELETE', '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'):
+        (204, '')
+    }
 
-    returncode, requests = run(event_data)
+    returncode, requests = run(event_data, responses)
 
     assert_success(returncode)
-    assert expected in requests
+    assert responses.keys()[0] in requests
 
 
 def test_synchronize_without_label():
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index a97ed7745d..1815873cff 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -112,7 +112,7 @@ def delete_tag(self, tag):
         logger.info('Deleting tag "{}"'.format(tag))
 
         try:
-            request(url, 'delete')
+            request(url, 'delete', ignore_body=True)
         except requests.HTTPError as exception:
             if exception.response.status_code != 404:
                 raise

From 107adfd275dbcac1e6b84c9ac7db00139b5c1ec2 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 15:47:28 -0400
Subject: [PATCH 13/23] Improve logging message

---
 tools/ci/update_pr_preview.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 1815873cff..837f470ed5 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -34,7 +34,7 @@ def request(url, method_name, data=None, json_data=None, params=None,
     }
     method = getattr(requests, method_name)
 
-    logger.info('Loading URL %s' % url)
+    logger.info('Issuing request: {} {}'.format(method_name.upper(), url))
     if json_data is not None or data is not None:
         kwargs['json'] = json_data
         kwargs['data'] = data

From 250aeaaf04999ec14bcbf6b730a9938342167670 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 15:48:52 -0400
Subject: [PATCH 14/23] Simplify helper function

---
 tools/ci/update_pr_preview.py | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 837f470ed5..4bd1a47b01 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -17,20 +17,14 @@ class Status(object):
     NEUTRAL = 78
 
 
-def request(url, method_name, data=None, json_data=None, params=None,
-            extra_headers=None, ignore_body=False):
+def request(url, method_name, data=None, json_data=None, ignore_body=False):
     github_token = os.environ.get('GITHUB_TOKEN')
-    headers = {
-        'Authorization': 'token {}'.format(github_token),
-        'Accept': 'application/vnd.github.machine-man-preview+json'
-    }
-
-    if extra_headers is not None:
-        headers.update(extra_headers)
 
     kwargs = {
-        'params': params,
-        'headers': headers
+        'headers': {
+            'Authorization': 'token {}'.format(github_token),
+            'Accept': 'application/vnd.github.machine-man-preview+json'
+        }
     }
     method = getattr(requests, method_name)
 

From e92ab0b442a82f26666f65294fcdd5dc4cec2d5c Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 17:07:49 -0400
Subject: [PATCH 15/23] Make test more realistic

---
 tools/ci/tests/test_update_pr_preview.py | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index 06aa83df0b..4501b0f86d 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -216,14 +216,15 @@ def test_add_active_label():
     event_data['pull_request']['labels'].append(
         {'name': 'pull-request-has-preview'}
     )
+    responses = {(
+        'GET', '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
+    ): (404, '{}')}
 
-    returncode, requests = run(event_data)
+    returncode, requests = run(event_data, responses)
 
     assert_success(returncode)
-    expected = (
-        'PATCH',
-        '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
-    )
+    expected = ('POST', '/repos/test-org/test-repo/git/refs')
+    assert responses.keys()[0] in requests
     assert expected in requests
 
 

From 3296ddbed70b1705ede15638ea95edff60a168cf Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 17:14:19 -0400
Subject: [PATCH 16/23] Manage tags and labels simultaneously

---
 tools/ci/tests/test_update_pr_preview.py | 26 +++++++++++++-----------
 tools/ci/update_pr_preview.py            | 21 +++++++++++++++----
 2 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/tools/ci/tests/test_update_pr_preview.py b/tools/ci/tests/test_update_pr_preview.py
index 4501b0f86d..c760bf2bfc 100644
--- a/tools/ci/tests/test_update_pr_preview.py
+++ b/tools/ci/tests/test_update_pr_preview.py
@@ -110,15 +110,19 @@ def test_close_active_with_label():
     event_data['pull_request']['labels'].append(
         {'name': 'pull-request-has-preview'}
     )
-    expected = (
+    delete_label = (
         'DELETE',
         '/repos/test-org/test-repo/issues/543/labels/pull-request-has-preview'
     )
+    delete_tag = (
+        'DELETE', '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'
+    )
 
     returncode, requests = run(event_data)
 
     assert_success(returncode)
-    assert expected in requests
+    assert delete_label in requests
+    assert delete_tag in requests
 
 
 def test_close_active_with_label_error():
@@ -166,22 +170,20 @@ def test_open_with_label():
 def test_open_without_label_for_collaborator():
     event_data = default_data('opened')
     responses = {
-        ('GET', '/repos/test-org/test-repo/collaborators/rms'): (204, '')
+        ('GET', '/repos/test-org/test-repo/collaborators/rms'): (204, ''),
+        ('GET', '/repos/test-org/test-repo/git/refs/tags/pr_preview_543'):
+            (404, '{}')
     }
 
     returncode, requests = run(event_data, responses)
 
     assert_success(returncode)
-    check_collaborator = (
-        'GET', '/repos/test-org/test-repo/collaborators/rms'
-    )
-    create_label = (
-        'POST',
-        '/repos/test-org/test-repo/issues/543/labels'
-    )
-    assert len(requests) == 2
-    assert check_collaborator in requests
+    create_label = ('POST', '/repos/test-org/test-repo/issues/543/labels')
+    create_tag = ('POST', '/repos/test-org/test-repo/git/refs')
+    assert responses.keys()[0] in requests
+    assert responses.keys()[1] in requests
     assert create_label in requests
+    assert create_tag in requests
 
 
 def test_open_without_label_for_non_collaborator():
diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 4bd1a47b01..863da036fe 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -177,9 +177,16 @@ def main(api_root):
 
     if not is_open:
         if action == 'closed' and has_label:
-            # This operation will trigger another GitHub Action which will
-            # subsequently delete the tag.
             github.remove_label(pr_number, active_label)
+
+            # > An action can't trigger other workflows. For example, a push,
+            # > deployment, or any task performed within an action with the
+            # > provided `GITHUB_TOKEN` will not trigger a workflow listening
+            # > on push, deploy, or any other supported action triggers.
+            #
+            # https://developer.github.com/actions/managing-workflows/workflow-configuration-options/
+            github.delete_tag(tag_name)
+
             return Status.SUCCESS
 
         return Status.NEUTRAL
@@ -187,9 +194,15 @@ def main(api_root):
     if action in ('opened', 'reopened') and has_label:
         github.tag(tag_name, sha)
     elif action in ('opened', 'reopened') and github.is_collaborator(login):
-        # This operation will trigger another GitHub Action which will
-        # subsequently create the tag.
         github.add_label(pr_number, active_label)
+
+        # > An action can't trigger other workflows. For example, a push,
+        # > deployment, or any task performed within an action with the
+        # > provided `GITHUB_TOKEN` will not trigger a workflow listening on
+        # > push, deploy, or any other supported action triggers.
+        #
+        # https://developer.github.com/actions/managing-workflows/workflow-configuration-options/
+        github.tag(tag_name, sha)
     elif action == 'labeled' and target_label == active_label:
         github.tag(tag_name, sha)
     elif action == 'unlabeled' and target_label == active_label:

From b419da74ba778900fb30c409656843886c034b37 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 17:18:03 -0400
Subject: [PATCH 17/23] Add debugging statement

---
 tools/ci/update_pr_preview.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 863da036fe..83e89b4de6 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -11,6 +11,12 @@
 logger = logging.getLogger(__name__)
 
 
+import subprocess
+logger.info(
+    subprocess.check_output(['git', 'rev-parse', 'HEAD'])
+)
+
+
 class Status(object):
     SUCCESS = 0
     FAIL = 1

From 5b3f859794b6d53c9f190f8215ad45a9710ce47f Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 17:48:02 -0400
Subject: [PATCH 18/23] Remove debugging statements

---
 tools/ci/update_pr_preview.py | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 83e89b4de6..863da036fe 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -11,12 +11,6 @@
 logger = logging.getLogger(__name__)
 
 
-import subprocess
-logger.info(
-    subprocess.check_output(['git', 'rev-parse', 'HEAD'])
-)
-
-
 class Status(object):
     SUCCESS = 0
     FAIL = 1

From fe9e488c83686846c6591749ded307a159744278 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 17:50:34 -0400
Subject: [PATCH 19/23] Improve formatting

---
 tools/ci/update_pr_preview.py | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 863da036fe..9c056edfca 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -168,13 +168,12 @@ def main(api_root):
     sha = event['pull_request']['head']['sha']
     is_open = event['pull_request']['closed_at'] is None
     login = event['pull_request']['user']['login']
-    has_label = any(
-        [label['name'] == active_label
-        for label in event['pull_request']['labels']]
-    )
+    has_label = any([
+        label['name'] == active_label
+        for label in event['pull_request']['labels']
+    ])
     target_label = event.get('label', {}).get('name')
 
-
     if not is_open:
         if action == 'closed' and has_label:
             github.remove_label(pr_number, active_label)

From 852ee214f89dd3d31c4cb2816fabb19d8411a2d9 Mon Sep 17 00:00:00 2001
From: Mike Pennisi <mike@mikepennisi.com>
Date: Mon, 8 Jul 2019 18:09:08 -0400
Subject: [PATCH 20/23] Add documentation

---
 tools/ci/update_pr_preview.py | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/ci/update_pr_preview.py b/tools/ci/update_pr_preview.py
index 9c056edfca..fe22614963 100644
--- a/tools/ci/update_pr_preview.py
+++ b/tools/ci/update_pr_preview.py
@@ -1,3 +1,30 @@
+# wpt-submissions.live is a public deployment of WPT, maintained in an external
+# repository. It automatically fetches and deploys all tags in the WPT
+# repository which match a certain pattern. This behavior is intended to be
+# used for pull requests so that reviewers can preview changes without running
+# the WPT server locally.
+#
+# This script facilitates the service by maintaining the git tags. It creates
+# and updates tags in response to GitHub events. It does this automatically for
+# pull requests from GitHub users who have "collaborator" access permissions to
+# the WPT repository. It also does this for any pull requests which bear the
+# `pull-request-has-preview` label. Collaborators can add or remove this label
+# to enable or disable the preview for submissions from non-collaborators.
+#
+# Although the script relies on secret access tokens, it is *not* limited to
+# use for pull requests from trusted collaborators due to the way GitHub
+# Actions are executed:
+#
+# > # Pull request events for forked repositories
+# >
+# > [...]
+# >
+# > ## Pull request with base and head branches in different repositories
+# >
+# > The base repository receives a pull_request event where the SHA is the
+# > latest commit of base branch and ref is the base branch.
+#
+# https://developer.github.com/actions/managing-workflows/workflow-configuration-options/#pull-request-events-for-forked-repositories
 import json
 import logging
 import os

From 13df69cc052f8111ada1383fd3326ae160b6765c Mon Sep 17 00:00:00 2001
From: jugglinmike-bocoup <mike+@bocoup.com>
Date: Mon, 8 Jul 2019 18:43:25 -0400
Subject: [PATCH 21/23] Add an empty file

---
 empty | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 empty

diff --git a/empty b/empty
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/empty
@@ -0,0 +1 @@
+

From 2575ea5bc0b276957b8962b166755314cdbe9267 Mon Sep 17 00:00:00 2001
From: jugglinmike-bocoup <mike+@bocoup.com>
Date: Mon, 8 Jul 2019 18:49:47 -0400
Subject: [PATCH 22/23] Add another empty file

---
 empty2 | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 empty2

diff --git a/empty2 b/empty2
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/empty2
@@ -0,0 +1 @@
+

From 091561469fcf5772716d13ba34a9389c8973be95 Mon Sep 17 00:00:00 2001
From: jugglinmike-bocoup <mike+@bocoup.com>
Date: Mon, 8 Jul 2019 18:55:52 -0400
Subject: [PATCH 23/23] Add a third empty file

---
 empty3 | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 empty3

diff --git a/empty3 b/empty3
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/empty3
@@ -0,0 +1 @@
+