Fix ReadingListEntry flaky unittests.

components/reading_list/ios/reading_list_entry_unittest.cc

 // Copyright 2016 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.
 
 #include "components/reading_list/ios/reading_list_entry.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/test/ios/wait_util.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "components/reading_list/ios/proto/reading_list.pb.h"
 #include "components/sync/protocol/reading_list_specifics.pb.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 const int kFirstBackoff = 10;
 const int kSecondBackoff = 10;
 const int kThirdBackoff = 60;
 const int kFourthBackoff = 120;
 const int kFifthBackoff = 120;
 
-// Returns the number of microseconds since Jan 1st 1970.
-int64_t Now() {
-  return (base::Time::Now() - base::Time::UnixEpoch()).InMicroseconds();
-}
 }  // namespace
 
 TEST(ReadingListEntry, CompareIgnoreTitle) {
   const ReadingListEntry e1(GURL("http://example.com"), "bar");
   const ReadingListEntry e2(GURL("http://example.com"), "foo");
 
   EXPECT_EQ(e1, e2);
 }
 
 TEST(ReadingListEntry, CompareFailureIgnoreTitle) {
@@ skipping 280 matching lines @@
   EXPECT_EQ(distilled_pb_entry->failed_download_counter(), 0);
   EXPECT_EQ(distilled_pb_entry->distillation_time_us(),
             entry.DistillationTime());
   EXPECT_EQ(distilled_pb_entry->distillation_size(), entry.DistillationSize());
 }
 
 // Tests that the reading list entry is correctly parsed from
 // sync_pb::ReadingListLocal.
 TEST(ReadingListEntry, FromReadingListLocal) {
   ReadingListEntry entry(GURL("http://example.com/"), "title");
-  base::Time next_call = base::Time::Now() + entry.TimeUntilNextTry();
+  entry.SetDistilledState(ReadingListEntry::ERROR);
 
   std::unique_ptr<reading_list::ReadingListLocal> pb_entry(
       entry.AsReadingListLocal());
-  int64_t now = Now();
+  int64_t now = 12345;
 
   pb_entry->set_entry_id("http://example.com/");
   pb_entry->set_url("http://example.com/");
   pb_entry->set_title("title");
   pb_entry->set_creation_time_us(1);
   pb_entry->set_update_time_us(2);
   pb_entry->set_status(reading_list::ReadingListLocal::UNREAD);
   pb_entry->set_distillation_state(reading_list::ReadingListLocal::WAITING);
   pb_entry->set_failed_download_counter(2);
   pb_entry->set_distillation_time_us(now);
   pb_entry->set_distillation_size(50);
 
   std::unique_ptr<ReadingListEntry> waiting_entry(
       ReadingListEntry::FromReadingListLocal(*pb_entry));
   EXPECT_EQ(waiting_entry->URL().spec(), "http://example.com/");
   EXPECT_EQ(waiting_entry->Title(), "title");
   EXPECT_EQ(waiting_entry->UpdateTime(), 2);
   EXPECT_EQ(waiting_entry->FailedDownloadCounter(), 2);
   EXPECT_EQ(waiting_entry->DistilledState(), ReadingListEntry::WAITING);
   EXPECT_EQ(waiting_entry->DistilledPath(), base::FilePath());
   EXPECT_EQ(waiting_entry->DistillationSize(), 50);
   EXPECT_EQ(waiting_entry->DistillationTime(), now);
-  base::Time waiting_next_call =
-      base::Time::Now() + waiting_entry->TimeUntilNextTry();
-  base::TimeDelta delta = next_call - waiting_next_call;
-  EXPECT_NEAR(delta.InMillisecondsRoundedUp(), 0, 10);
+  double fuzzing = ReadingListEntry::kBackoffPolicy.jitter_factor;
+  int nextTry = waiting_entry->TimeUntilNextTry().InMinutes();
+  EXPECT_NEAR(kFirstBackoff, nextTry, kFirstBackoff * fuzzing);
 }
 
 // Tests the merging of two ReadingListEntry.
 // Additional merging tests are done in
 // ReadingListStoreTest.CompareEntriesForSync
 TEST(ReadingListEntry, MergeWithEntry) {
   ReadingListEntry local_entry(GURL("http://example.com/"), "title");
   local_entry.SetDistilledState(ReadingListEntry::ERROR);
-  base::Time next_call = base::Time::Now() + local_entry.TimeUntilNextTry();
   int64_t local_update_time_us = local_entry.UpdateTime();
 
   ReadingListEntry sync_entry(GURL("http://example.com/"), "title2");
   sync_entry.SetDistilledState(ReadingListEntry::ERROR);
   int64_t sync_update_time_us = sync_entry.UpdateTime();
   EXPECT_NE(local_update_time_us, sync_update_time_us);
   local_entry.MergeWithEntry(sync_entry);
   EXPECT_EQ(local_entry.URL().spec(), "http://example.com/");
   EXPECT_EQ(local_entry.Title(), "title2");
   EXPECT_FALSE(local_entry.HasBeenSeen());
   EXPECT_EQ(local_entry.UpdateTime(), sync_update_time_us);
   EXPECT_EQ(local_entry.FailedDownloadCounter(), 1);
   EXPECT_EQ(local_entry.DistilledState(), ReadingListEntry::ERROR);
-  base::Time merge_next_call =
-      base::Time::Now() + local_entry.TimeUntilNextTry();
-  base::TimeDelta delta = merge_next_call - next_call;
-  EXPECT_NEAR(delta.InMillisecondsRoundedUp(), 0, 10);
+  double fuzzing = ReadingListEntry::kBackoffPolicy.jitter_factor;
+  int nextTry = local_entry.TimeUntilNextTry().InMinutes();
+  EXPECT_NEAR(kFirstBackoff, nextTry, kFirstBackoff * fuzzing);
 }