[Telemetry] Fix WPR files not being downloaded when required.

tools/telemetry/telemetry/wpr/archive_info_unittest.py

Index: tools/telemetry/telemetry/wpr/archive_info_unittest.py
diff --git a/tools/telemetry/telemetry/wpr/archive_info_unittest.py b/tools/telemetry/telemetry/wpr/archive_info_unittest.py
index 0916f0953094c2977291ccccd1f6a7bb6acc0665..32b7697bdfd82e9b1cc69c2a2ded1c39690fc3bd 100644
--- a/tools/telemetry/telemetry/wpr/archive_info_unittest.py
+++ b/tools/telemetry/telemetry/wpr/archive_info_unittest.py
@@ -8,6 +8,7 @@ import tempfile
 import unittest
 
 from telemetry.page import page
+from telemetry.unittest_util import system_stub
 from telemetry.util import cloud_storage
 from telemetry.wpr import archive_info
 
@@ -35,6 +36,7 @@ archive_info_contents = ("""
 
 class WprArchiveInfoTest(unittest.TestCase):
   def setUp(self):
+    self._overrides = system_stub.Override(archive_info, ['cloud_storage'])
     self.tmp_dir = tempfile.mkdtemp()
     # Write the metadata.
     self.user_story_set_archive_info_file = os.path.join(
@@ -53,12 +55,26 @@ class WprArchiveInfoTest(unittest.TestCase):
 
   def tearDown(self):
     shutil.rmtree(self.tmp_dir)
+    self._overrides.Restore()
 
   def assertCorrectHashFile(self, file_path):
     self.assertTrue(os.path.exists(file_path + '.sha1'))
     with open(file_path + '.sha1', 'rb') as f:
       self.assertEquals(cloud_storage.CalculateHash(file_path), f.read())
 
+  def testDownloadArchivesIfNeeded(self):
+    cloud_storage_stub = self._overrides.cloud_storage
+    # Second hash doesn't match, need to fetch it.
+    cloud_storage_stub.SetRemotePathsForTesting(
+        {cloud_storage.PUBLIC_BUCKET: {recording1: "dummyhash",
+                                       recording2: "dummyhash22"}})
+    cloud_storage_stub.SetCalculatedHashesForTesting(
+        {os.path.join(self.tmp_dir, recording1): "dummyhash",
+         os.path.join(self.tmp_dir, recording2): "dummyhash2",})
+    self.archive_info.DownloadArchivesIfNeeded()
+    self.assertEquals(len(cloud_storage_stub.downloaded_files), 1)
+    self.assertEquals(cloud_storage_stub.downloaded_files[0], recording2)
+
   def testReadingArchiveInfo(self):
     self.assertIsNotNone(self.archive_info.WprFilePathForUserStory(page1))
     self.assertEquals(recording1, os.path.basename(