Devserver: allow SubversionFileSystem to be pinned to a specific rev on construction

chrome/common/extensions/docs/server2/cron_servlet_test.py

 #!/usr/bin/env python
 # Copyright 2013 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.
 
 import unittest
 
+from appengine_wrappers import GetAppVersion
+from app_yaml_helper import AppYamlHelper
 from cron_servlet import CronServlet
 from empty_dir_file_system import EmptyDirFileSystem
 from local_file_system import LocalFileSystem
 from mock_file_system import MockFileSystem
 from servlet import Request
 from test_branch_utility import TestBranchUtility
 from test_file_system import TestFileSystem
 from test_util import EnableLogging
 
 # NOTE(kalman): The ObjectStore created by the CronServlet is backed onto our
-# fake AppEngine memcache/datastore, so the tests aren't isolated.
+# fake AppEngine memcache/datastore, so the tests aren't isolated. Of course,
+# if the host file systems have different identities, they will be, sort of.
 class _TestDelegate(CronServlet.Delegate):
-  def __init__(self):
-    self.host_file_systems = []
+  def __init__(self, create_file_system):
+    self.file_systems = []
+    # A callback taking a revision and returning a file system.
+    self._create_file_system = create_file_system
+    self._app_version = GetAppVersion()
 
   def CreateBranchUtility(self, object_store_creator):
     return TestBranchUtility()
 
-  def CreateHostFileSystemForBranch(self, branch):
-    host_file_system = MockFileSystem(LocalFileSystem.Create())
-    self.host_file_systems.append(host_file_system)
-    return host_file_system
+  def CreateHostFileSystemForBranchAndRevision(self, branch, revision):
+    file_system = self._create_file_system(revision)
+    self.file_systems.append(file_system)
+    return file_system
 
   def CreateAppSamplesFileSystem(self, object_store_creator):
     return EmptyDirFileSystem()
 
+  def GetAppVersion(self):
+    return self._app_version
+
+  # (non-Delegate method).
+  def SetAppVersion(self, app_version):
+    self._app_version = app_version
+
 class CronServletTest(unittest.TestCase):
   @EnableLogging('info')
   def testEverything(self):
     # All these tests are dependent (see above comment) so lump everything in
     # the one test.
-    delegate = _TestDelegate()
+    delegate = _TestDelegate(lambda _: MockFileSystem(LocalFileSystem.Create()))
 
     # Test that the cron runs successfully.
     response = CronServlet(Request.ForTest('trunk'),
                            delegate_for_test=delegate).Get()
-    self.assertEqual(1, len(delegate.host_file_systems))
+    self.assertEqual(1, len(delegate.file_systems))
     self.assertEqual(200, response.status)
 
     # When re-running, all file systems should be Stat()d the same number of
     # times, but the second round shouldn't have been re-Read() since the
     # Stats haven't changed.
     response = CronServlet(Request.ForTest('trunk'),
                            delegate_for_test=delegate).Get()
-    self.assertEqual(2, len(delegate.host_file_systems))
-    self.assertTrue(*delegate.host_file_systems[1].CheckAndReset(
+    self.assertEqual(2, len(delegate.file_systems))
+    self.assertTrue(*delegate.file_systems[1].CheckAndReset(
         read_count=0,
-        stat_count=delegate.host_file_systems[0].GetStatCount()))
+        stat_count=delegate.file_systems[0].GetStatCount()))
 
+  def testSafeRevision(self):
+    test_data = {
+      'docs': {
+        'examples': {
+          'examples.txt': 'examples.txt contents'
+        },
+        'server2': {
+          'app.yaml': AppYamlHelper.GenerateAppYaml('2-0-8')
+        },
+        'static': {
+          'static.txt': 'static.txt contents'
+        },
+        'templates': {
+          'public': {
+            'apps': {
+              'storage.html': 'storage.html contents'
+            },
+            'extensions': {
+              'storage.html': 'storage.html contents'
+            },
+          }
+        }
+      }
+    }
+
+    updates = []
+
+    def app_yaml_update(version):
+      return {'docs': {'server2': {
+        'app.yaml': AppYamlHelper.GenerateAppYaml(version)
+      }}}
+    def storage_html_update(update):
+      return {'docs': {'templates': {'public': {'apps': {
+        'storage.html': update
+      }}}}}
+    def static_txt_update(update):
+      return {'docs': {'static': {
+        'static.txt': update
+      }}}
+
+    app_yaml_path = 'docs/server2/app.yaml'
+    storage_html_path = 'docs/templates/public/apps/storage.html'
+    static_txt_path = 'docs/static/static.txt'
+
+    def create_file_system(revision):
+      '''Creates a MockFileSystem at |revision| by applying that many |updates|
+      to it.
+      '''
+      mock_file_system = MockFileSystem(TestFileSystem(test_data))
+      for update in updates[:revision]:
+        mock_file_system.Update(update)
+      return mock_file_system
+
+    delegate = _TestDelegate(create_file_system)
+    delegate.SetAppVersion('2-0-8')
+
+    file_systems = delegate.file_systems
+
+    # No updates applied yet.
+    CronServlet(Request.ForTest('trunk'), delegate_for_test=delegate).Get()
+    self.assertEqual(AppYamlHelper.GenerateAppYaml('2-0-8'),
+                     file_systems[-1].ReadSingle(app_yaml_path))
+    self.assertEqual('storage.html contents',
+                     file_systems[-1].ReadSingle(storage_html_path))
+
+    # Apply updates to storage.html.
+    updates.append(storage_html_update('interim contents'))
+    updates.append(storage_html_update('new contents'))
+
+    CronServlet(Request.ForTest('trunk'), delegate_for_test=delegate).Get()
+    self.assertEqual(AppYamlHelper.GenerateAppYaml('2-0-8'),
+                     file_systems[-1].ReadSingle(app_yaml_path))
+    self.assertEqual('new contents',
+                     file_systems[-1].ReadSingle(storage_html_path))
+
+    # Apply several updates to storage.html and app.yaml. The file system
+    # should be pinned at the version before app.yaml changed.
+    updates.append(storage_html_update('stuck here contents'))
+
+    double_update = storage_html_update('newer contents')
+    double_update.update(app_yaml_update('2-0-10'))
+    updates.append(double_update)
+
+    updates.append(storage_html_update('never gonna reach here'))
+
+    CronServlet(Request.ForTest('trunk'), delegate_for_test=delegate).Get()
+    self.assertEqual(AppYamlHelper.GenerateAppYaml('2-0-8'),
+                     file_systems[-1].ReadSingle(app_yaml_path))
+    self.assertEqual('stuck here contents',
+                     file_systems[-1].ReadSingle(storage_html_path))
+
+    # Further pushes to storage.html will keep it pinned.
+    updates.append(storage_html_update('y u not update!'))
+
+    CronServlet(Request.ForTest('trunk'), delegate_for_test=delegate).Get()
+    self.assertEqual(AppYamlHelper.GenerateAppYaml('2-0-8'),
+                     file_systems[-1].ReadSingle(app_yaml_path))
+    self.assertEqual('stuck here contents',
+                     file_systems[-1].ReadSingle(storage_html_path))
+
+    # Likewise app.yaml.
+    updates.append(app_yaml_update('2-1-0'))
+
+    CronServlet(Request.ForTest('trunk'), delegate_for_test=delegate).Get()
+    self.assertEqual(AppYamlHelper.GenerateAppYaml('2-0-8'),
+                     file_systems[-1].ReadSingle(app_yaml_path))
+    self.assertEqual('stuck here contents',
+                     file_systems[-1].ReadSingle(storage_html_path))
+
+    # And updates to other content won't happen either.
+    updates.append(static_txt_update('important content!'))
+
+    CronServlet(Request.ForTest('trunk'), delegate_for_test=delegate).Get()
+    self.assertEqual(AppYamlHelper.GenerateAppYaml('2-0-8'),
+                     file_systems[-1].ReadSingle(app_yaml_path))
+    self.assertEqual('stuck here contents',
+                     file_systems[-1].ReadSingle(storage_html_path))
+    self.assertEqual('static.txt contents',
+                     file_systems[-1].ReadSingle(static_txt_path))
+
+    # Lastly - when the app version changes, everything should no longer be
+    # pinned.
+    delegate.SetAppVersion('2-1-0')
+    CronServlet(Request.ForTest('trunk'), delegate_for_test=delegate).Get()
+    self.assertEqual(AppYamlHelper.GenerateAppYaml('2-1-0'),
+                     file_systems[-1].ReadSingle(app_yaml_path))
+    self.assertEqual('y u not update!',
+                     file_systems[-1].ReadSingle(storage_html_path))
+    self.assertEqual('important content!',
+                     file_systems[-1].ReadSingle(static_txt_path))
 
 if __name__ == '__main__':
   unittest.main()