[NTP Snippets] Persist snippets in a LevelDB instead of prefs

components/ntp_snippets/ntp_snippets_service_unittest.cc

Index: components/ntp_snippets/ntp_snippets_service_unittest.cc
diff --git a/components/ntp_snippets/ntp_snippets_service_unittest.cc b/components/ntp_snippets/ntp_snippets_service_unittest.cc
index 0141584b4fcd151e524693a5ea8e584807859773..7bb3678b9b11c5fcd4d9ce237dc49958a2e9c9fd 100644
--- a/components/ntp_snippets/ntp_snippets_service_unittest.cc
+++ b/components/ntp_snippets/ntp_snippets_service_unittest.cc
@@ -8,6 +8,8 @@
 #include <vector>
 
 #include "base/command_line.h"
+#include "base/files/file_path.h"
+#include "base/files/scoped_temp_dir.h"
 #include "base/json/json_reader.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ -21,6 +23,7 @@
 #include "base/time/time.h"
 #include "components/image_fetcher/image_fetcher.h"
 #include "components/ntp_snippets/ntp_snippet.h"
+#include "components/ntp_snippets/ntp_snippets_database.h"
 #include "components/ntp_snippets/ntp_snippets_fetcher.h"
 #include "components/ntp_snippets/ntp_snippets_scheduler.h"
 #include "components/ntp_snippets/switches.h"
@@ -236,6 +239,33 @@ class MockServiceObserver : public NTPSnippetsServiceObserver {
   MOCK_METHOD0(NTPSnippetsServiceDisabled, void());
 };
 
+class WaitForDBLoad : public NTPSnippetsServiceObserver {
+ public:
+  WaitForDBLoad(NTPSnippetsService* service) : service_(service) {
+    EXPECT_TRUE(!service_->loaded());
+    service_->AddObserver(this);
+    run_loop_.Run();

[Bernhard Bauer, 2016/05/25 15:01:15]

If you already have an object for this, you could move the Run() to a separate
method, so you can create this first, then call Init() on the service, then wait
for it to finish. That way it will also work if the service finishes loading
synchronously.

[Marc Treib, 2016/05/27 14:03:12]

Init() doesn't exist anymore :)
I guess we could return early if the service is already loaded, but since that
can't happen right now, I'd prefer to keep this as-is.

[Bernhard Bauer, 2016/05/27 16:06:43]

It's a bit of a defense-in-depth thing: if you at some point in the future
should notify synchronously, you might start failing in this test. The test code
is a common pattern: First set up the observer, then do the action, then wait
for the observation.

[Marc Treib, 2016/05/30 13:22:00]

This pattern isn't possible anymore, since the NTPSnippetsService ctor
immediately starts the DB load.
I have changed the helper to also handle the case when the DB is already loaded,
so it'll continue to work if that ever becomes synchronous.

+  }
+
+  ~WaitForDBLoad() override {
+    service_->RemoveObserver(this);
+  }
+
+ private:
+  void NTPSnippetsServiceLoaded() override {
+    EXPECT_TRUE(service_->loaded());
+    run_loop_.Quit();
+  }
+
+  void NTPSnippetsServiceShutdown() override {};

[Bernhard Bauer, 2016/05/25 15:01:15]

No semicolon

[Marc Treib, 2016/05/27 14:03:13]

Done.

+  void NTPSnippetsServiceDisabled() override {};
+
+  NTPSnippetsService* service_;
+  base::RunLoop run_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaitForDBLoad);
+};
+
 }  // namespace
 
 class NTPSnippetsServiceTest : public testing::Test {
@@ -256,6 +286,7 @@ class NTPSnippetsServiceTest : public testing::Test {
     // service to fetch from all hosts.
     base::CommandLine::ForCurrentProcess()->AppendSwitch(
         switches::kDontRestrict);
+    EXPECT_TRUE(database_dir_.CreateUniqueTempDir());
   }
 
   ~NTPSnippetsServiceTest() override {
@@ -277,15 +308,23 @@ class NTPSnippetsServiceTest : public testing::Test {
     scoped_refptr<net::TestURLRequestContextGetter> request_context_getter =
         new net::TestURLRequestContextGetter(task_runner.get());
 
+    // Delete the current service, so that the database is destroyed before we
+    // create the new one, otherwise opening the new database will fail.
+    service_.reset();
+
     service_.reset(new NTPSnippetsService(
-        pref_service_.get(), mock_sync_service_.get(), nullptr, task_runner,
+        pref_service_.get(), mock_sync_service_.get(), nullptr,
         std::string("fr"), &scheduler_,
         base::WrapUnique(new NTPSnippetsFetcher(
             fake_signin_manager_.get(), fake_token_service_.get(),
             std::move(request_context_getter), base::Bind(&ParseJson),
             /*is_stable_channel=*/true)),
-        /*image_fetcher=*/nullptr));
+        /*image_fetcher=*/nullptr,
+        base::WrapUnique(new NTPSnippetsDatabase(database_dir_.path(),
+                                                 task_runner))));
     service_->Init(enabled);
+    if (enabled)
+      WaitForDBLoad(service_.get());
   }
 
  protected:
@@ -339,6 +378,8 @@ class NTPSnippetsServiceTest : public testing::Test {
   // Last so that the dependencies are deleted after the service.
   std::unique_ptr<NTPSnippetsService> service_;
 
+  base::ScopedTempDir database_dir_;
+
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsServiceTest);
 };