Make chrome ios smoke tests aware of Seed File.

Before this CL, the test only checks Local State, now it checks the seed
file, to make sure that the seed is stored in a file.

To achieve that, it changes the way that the seed is injected into the
test, so when it inject a seed, it writes to both Local State and the
VariationsSeedV1 file.

Also it waits if a write is in progress, to make sure the check happens
after the seed is written.

Bug: 413580167

Change-Id: Iac24ccfda2859afaf86643905d18c1042eea65ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6546896
Reviewed-by: Ernest Nguyen Hung <ernn@google.com>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Commit-Queue: Ramon Cano Aparicio <rcanoaparicio@google.com>
Cr-Commit-Position: refs/heads/main@{#1464597}

components/variations/seed_reader_writer.cc

@@ -324,4 +324,8 @@ bool SeedReaderWriter::ShouldUseSeedFile() const {
          base::FieldTrialList::FindFullName(kSeedFileTrial) == kSeedFilesGroup;
 }
 
+bool SeedReaderWriter::HasPendingWrite() const {
+  return seed_writer_ && seed_writer_->HasPendingWrite();
+}
+
 }  // namespace variations

components/variations/seed_reader_writer.h

@@ -115,6 +115,9 @@ class COMPONENT_EXPORT(VARIATIONS) SeedReaderWriter
   // Overrides the timer used for scheduling writes with `timer_override`.
   void SetTimerForTesting(base::OneShotTimer* timer_override);
 
+  // Returns true if a write is scheduled but has not yet completed.
+  bool HasPendingWrite() const;
+
  private:
   // TODO(crbug.com/380465790): Represents the seed and other related info.
   // This info will be stored together in the SeedFile. Once all the

ios/build/bots/scripts/variations_runner.py

@@ -135,10 +135,7 @@ class VariationsSimulatorParallelTestRunner(SimulatorParallelTestRunner):
     seed, signature = seed_helper.load_test_seed_from_file(
         self.variations_seed_path)
     if not seed or not signature:
-      log = ('Ill-formed test seed json file: "%s" and "%s" are required',
-             seed_helper.LOCAL_STATE_SEED_NAME,
-             seed_helper.LOCAL_STATE_SEED_SIGNATURE_NAME)
-      return False, log
+      return False, seed_helper.ILL_FORMED_TEST_SEED_ERROR_MESSAGE
     if not seed_helper.inject_test_seed(seed, signature, self._user_data_dir()):
       log = 'Failed to inject test seed.'
       LOGGER.error(log)

ios/chrome/test/variations_smoke_test/variations_smoke_test_app_interface.mm

@@ -32,13 +32,14 @@ base::Time GetProcessStartTime() {
 @implementation VariationsSmokeTestAppInterface
 
 + (BOOL)variationsSeedInLocalStatePrefs {
-  variations::StoredSeed storedSeed = GetApplicationContext()
-                                          ->GetVariationsService()
-                                          ->GetSeedStoreForTesting()
-                                          ->GetSeedReaderWriterForTesting()
-                                          ->GetSeedData();
-
-  return !storedSeed.data.empty() && !storedSeed.signature.empty();
+  variations::SeedReaderWriter* seedReaderWriter =
+      GetApplicationContext()
+          ->GetVariationsService()
+          ->GetSeedStoreForTesting()
+          ->GetSeedReaderWriterForTesting();
+  variations::StoredSeed storedSeed = seedReaderWriter->GetSeedData();
+  return !storedSeed.data.empty() && !storedSeed.signature.empty() &&
+         !seedReaderWriter->HasPendingWrite();
 }
 
 + (BOOL)variationsSeedFetchedInCurrentLaunch {

testing/scripts/run_variations_smoke_tests.py

@@ -192,9 +192,7 @@ def _inject_seed(user_data_dir, path_chromedriver, chrome_options):
       'variations_seed_beta_%s.json' % _get_platform())
   seed, signature = seed_helper.load_test_seed_from_file(hardcoded_seed_path)
   if not seed or not signature:
-    logging.error('Ill-formed test seed json file: "%s" and "%s" are required',
-                  seed_helper.LOCAL_STATE_SEED_NAME,
-                  seed_helper.LOCAL_STATE_SEED_SIGNATURE_NAME)
+    logging.error(seed_helper.ILL_FORMED_TEST_SEED_ERROR_MESSAGE)
     return 1
 
   if not seed_helper.inject_test_seed(seed, signature, user_data_dir):

testing/scripts/variations_seed_access_helper.py

@@ -1,8 +1,16 @@
 # Copyright 2021 The Chromium Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
-"""Shared helper functions for r/w of variations seed in local state."""
+"""Shared helper functions for r/w of variations seed in local state.
 
+# TODO(crbug.com/417138763): Update comment with new format.
+The seed is can be stored in either the local state file or the seed file.
+ - When stored in the seed file, the seed is stored compressed with gzip format.
+ - When stored in the local state file, the seed is compressed with gzip format
+   and encoded into base64.
+"""
+
+import base64
 import json
 import logging
 import os
@@ -12,8 +20,12 @@ _SRC_DIR = os.path.join(_THIS_DIR, os.path.pardir, os.path.pardir)
 
 # Constants around the Local State file and variation keys.
 _LOCAL_STATE_FILE_NAME = 'Local State'
-LOCAL_STATE_SEED_NAME = 'variations_compressed_seed'
-LOCAL_STATE_SEED_SIGNATURE_NAME = 'variations_seed_signature'
+_VARIATIONS_SEED_FILE_NAME = 'VariationsSeedV1'
+_SEED_KEY = 'variations_compressed_seed'
+_SEED_SIGNATURE_KEY = 'variations_seed_signature'
+ILL_FORMED_TEST_SEED_ERROR_MESSAGE = (
+    f'Ill-formed test seed json file: "{_SEED_KEY}" and "{_SEED_SIGNATURE_KEY}"'
+    ' are required')
 
 
 def load_test_seed_from_file(hardcoded_seed_path):
@@ -45,8 +57,8 @@ def load_test_seed_from_file(hardcoded_seed_path):
   with open(path_seed, 'r') as f:
     seed_json = json.load(f)
 
-  return (seed_json.get(LOCAL_STATE_SEED_NAME, None),
-          seed_json.get(LOCAL_STATE_SEED_SIGNATURE_NAME, None))
+  return (seed_json.get(_SEED_KEY,
+                        None), seed_json.get(_SEED_SIGNATURE_KEY, None))
 
 
 def get_test_seed_file_path(hardcoded_seed_path):
@@ -77,6 +89,8 @@ def get_test_seed_file_path(hardcoded_seed_path):
   return path_seed
 
 
+# TODO(crbug.com/417138763): Update this function to support reading the seed
+# from the seed file with proto format.
 def get_current_seed(user_data_dir):
   """Gets the current seed.
 
@@ -89,9 +103,62 @@ def get_current_seed(user_data_dir):
   with open(os.path.join(user_data_dir, _LOCAL_STATE_FILE_NAME)) as f:
     local_state = json.load(f)
 
-  return local_state.get(LOCAL_STATE_SEED_NAME,
-                         None), local_state.get(LOCAL_STATE_SEED_SIGNATURE_NAME,
-                                                None)
+  # Try to read the seed from the seed file first. If the file doesn't exist,
+  # read from local state.
+  seed_file_path = os.path.join(user_data_dir, _VARIATIONS_SEED_FILE_NAME)
+  if os.path.exists(seed_file_path):
+    with open(seed_file_path, 'rb') as f:
+      seed_file = f.read()
+      # The seed was originally stored compressed and base64-encoded in Local
+      # State. We encode it again to match the expected format.
+      seed = base64.b64encode(seed_file).decode('ascii')
+  else:
+    # The seed from Local State is already compressed and base64-encoded.
+    seed = local_state.get(_SEED_KEY, None)
+  signature = local_state.get(_SEED_SIGNATURE_KEY, None)
+
+  return seed, signature
+
+
+def _update_seed_file(user_data_dir, seed_dict):
+  """Updates the seed in the seed file.
+
+  The seed is stored compressed with gzip format.
+
+  Args:
+    user_data_dir (str): Path to the user data directory used to launch Chrome.
+    seed_dict (dict): A dict used to update current seed file.
+  """
+  # The seed is stored compressed with gzip format in the seed file.
+  decoded_seed = base64.b64decode(seed_dict.get(_SEED_KEY, None))
+  with open(os.path.join(user_data_dir, _VARIATIONS_SEED_FILE_NAME), 'wb') as f:
+    f.write(decoded_seed)
+
+  # The signature is stored in Local State.
+  # TODO(crbug.com/411431524): Store the signature in the seed file.
+  update_local_state(user_data_dir, {
+      _SEED_SIGNATURE_KEY: seed_dict.get(_SEED_SIGNATURE_KEY),
+  })
+
+
+# TODO(crbug.com/417138763): Update this function to support updating the seed
+# to the seed file with proto format.
+def update_seed(user_data_dir, seed, signature):
+  """Updates the seed in the local state and seed file.
+
+  Args:
+    user_data_dir (str): Path to the user data directory used to launch Chrome.
+    seed (str): A variations seed.
+    signature (str): A seed signature.
+  """
+  seed_dict = {
+      _SEED_KEY: seed,
+      _SEED_SIGNATURE_KEY: signature,
+  }
+
+  update_local_state(user_data_dir, seed_dict)
+  _update_seed_file(user_data_dir, seed_dict)
+
 
 
 def update_local_state(user_data_dir, update_dict):
@@ -121,11 +188,7 @@ def inject_test_seed(seed, signature, user_data_dir):
   Returns:
     bool: Whether the injection succeeded.
   """
-  seed_dict = {
-      LOCAL_STATE_SEED_NAME: seed,
-      LOCAL_STATE_SEED_SIGNATURE_NAME: signature,
-  }
-  update_local_state(user_data_dir, seed_dict)
+  update_seed(user_data_dir, seed, signature)
   current_seed, current_signature = get_current_seed(user_data_dir)
   if current_seed != seed or current_signature != signature:
     return False