RemoteContentSuggestions: Stores the time of the last successful background fetch in a pref

components/ntp_snippets/remote/remote_suggestions_provider_unittest.cc

Index: components/ntp_snippets/remote/remote_suggestions_provider_unittest.cc
diff --git a/components/ntp_snippets/remote/remote_suggestions_provider_unittest.cc b/components/ntp_snippets/remote/remote_suggestions_provider_unittest.cc
index b593ee4958589942d58af50c81b03cf56d745b34..f809e1e18d7ae1eb4baa9122159f2aaac663af5a 100644
--- a/components/ntp_snippets/remote/remote_suggestions_provider_unittest.cc
+++ b/components/ntp_snippets/remote/remote_suggestions_provider_unittest.cc
@@ -20,6 +20,7 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/test/histogram_tester.h"
+#include "base/test/simple_test_tick_clock.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "components/image_fetcher/image_decoder.h"
@@ -1593,4 +1594,35 @@ TEST_F(RemoteSuggestionsProviderTest,
               SizeIs(service->GetMaxSnippetCountForTesting() + 1));
 }
 
+TEST_F(RemoteSuggestionsProviderTest, StoreLastSuccessfullBackgroundFetchTime) {
+  // On initialization of the RemoteSuggestionsProvider a background fetch is
+  // triggered since the snippets DB is empty. Therefore the service must not be
+  // initialized until the test clock is set.
+  auto service = MakeSnippetsServiceWithoutInitialization();
+
+  auto simple_test_tick_clock = base::MakeUnique<base::SimpleTestTickClock>();
+  base::SimpleTestTickClock* simple_test_tick_clock_ptr =
+      simple_test_tick_clock.get();
+  service->SetTickClockForTesting(std::move(simple_test_tick_clock));
+
+  // Test that the preference is correctly initialized with the default value 0.
+  EXPECT_EQ(
+      0, pref_service()->GetInt64(prefs::kLastSuccessfulBackgroundFetchTime));
+
+  WaitForSnippetsServiceInitialization(service.get(),
+                                       /*set_empty_response=*/true);
+  EXPECT_EQ(
+      simple_test_tick_clock_ptr->NowTicks().ToInternalValue(),
+      pref_service()->GetInt64(prefs::kLastSuccessfulBackgroundFetchTime));
+
+  // Advance the time and check whether the time was updated correctly after the
+  // background fetch.
+  simple_test_tick_clock_ptr->Advance(TimeDelta::FromHours(1));
+  service->FetchSnippetsInTheBackground();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(
+      simple_test_tick_clock_ptr->NowTicks().ToInternalValue(),
+      pref_service()->GetInt64(prefs::kLastSuccessfulBackgroundFetchTime));
+}
+
 }  // namespace ntp_snippets