[NTP] Test ContextualSuggestionsSource

Add FakeContextualSuggestionsFetcher, 
MockFetchContextualSuggestionsCallback and a unittest 
for ContextualSuggestionsSource suggestion fetching.

Bug: 749988
Change-Id: I958744e74fa54204d5dd764da49fc2ca45d6b9b3
Reviewed-on: https://chromium-review.googlesource.com/593656
Commit-Queue: Andre Gaschler <gaschler@chromium.org>
Reviewed-by: vitaliii <vitaliii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490967}

components/ntp_snippets/BUILD.gn

@@ -179,6 +179,7 @@ source_set("unit_tests") {
     "category_unittest.cc",
     "content_suggestions_metrics_unittest.cc",
     "content_suggestions_service_unittest.cc",
+    "contextual_suggestions_source_unittest.cc",
     "offline_pages/recent_tab_suggestions_provider_unittest.cc",
     "physical_web_pages/physical_web_page_suggestions_provider_unittest.cc",
     "reading_list/reading_list_suggestions_provider_unittest.cc",

components/ntp_snippets/contextual_suggestions_source_unittest.cc

+// Copyright 2017 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/ntp_snippets/contextual_suggestions_source.h"
+
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "components/image_fetcher/core/image_fetcher_impl.h"
+#include "components/ntp_snippets/category_info.h"
+#include "components/ntp_snippets/content_suggestion.h"
+#include "components/ntp_snippets/remote/cached_image_fetcher.h"
+#include "components/ntp_snippets/remote/contextual_suggestions_fetcher.h"
+#include "components/ntp_snippets/remote/json_to_categories.h"
+#include "components/ntp_snippets/remote/remote_suggestion.h"
+#include "components/ntp_snippets/remote/remote_suggestions_database.h"
+#include "components/ntp_snippets/remote/test_utils.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using testing::_;
+using testing::AllOf;
+using testing::ElementsAre;
+using testing::Mock;
+using testing::Pointee;
+using testing::Property;
+
+namespace ntp_snippets {
+
+namespace {
+
+const char kFromURL[] = "http://localhost";
+const char kSuggestionURL[] = "http://url.test";
+
+// Always fetches one valid RemoteSuggestion.
+class FakeContextualSuggestionsFetcher : public ContextualSuggestionsFetcher {
+  void FetchContextualSuggestions(
+      const GURL& url,
+      SuggestionsAvailableCallback callback) override {
+    OptionalSuggestions suggestions = RemoteSuggestion::PtrVector();
+    suggestions->push_back(test::RemoteSuggestionBuilder()
+                               .AddId(kSuggestionURL)
+                               .SetUrl(kSuggestionURL)
+                               .SetAmpUrl(kSuggestionURL)
+                               .Build());
+    std::move(callback).Run(Status::Success(), std::move(suggestions));
+  }
+
+  const std::string& GetLastStatusForTesting() const override { return empty_; }
+  const std::string& GetLastJsonForTesting() const override { return empty_; }
+  const GURL& GetFetchUrlForTesting() const override { return empty_url_; }
+
+ private:
+  std::string empty_;
+  GURL empty_url_;
+};
+
+// GMock does not support movable-only types (ContentSuggestion).
+// Instead WrappedRun is used as callback and it redirects the call to a
+// method without movable-only types, which is then mocked.
+class MockFetchContextualSuggestionsCallback {
+ public:
+  void WrappedRun(Status status,
+                  const GURL& url,
+                  std::vector<ContentSuggestion> suggestions) {
+    Run(status, url, &suggestions);
+  }
+
+  ContextualSuggestionsSource::FetchContextualSuggestionsCallback
+  ToOnceCallback() {
+    return base::BindOnce(&MockFetchContextualSuggestionsCallback::WrappedRun,
+                          base::Unretained(this));
+  }
+
+  MOCK_METHOD3(Run,
+               void(Status status_code,
+                    const GURL& url,
+                    std::vector<ContentSuggestion>* suggestions));
+};
+
+}  // namespace
+
+class ContextualSuggestionsSourceTest : public testing::Test {
+ public:
+  ContextualSuggestionsSourceTest() {
+    source_ = base::MakeUnique<ContextualSuggestionsSource>(
+        base::MakeUnique<FakeContextualSuggestionsFetcher>(),
+        std::unique_ptr<CachedImageFetcher>(),
+        std::unique_ptr<RemoteSuggestionsDatabase>());
+  }
+
+  ContextualSuggestionsSource* source() { return source_.get(); }
+
+ private:
+  base::MessageLoop message_loop_;
+  std::unique_ptr<ContextualSuggestionsSource> source_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContextualSuggestionsSourceTest);
+};
+
+TEST_F(ContextualSuggestionsSourceTest, ShouldFetchContextualSuggestion) {
+  MockFetchContextualSuggestionsCallback mock_suggestions_callback;
+  EXPECT_CALL(
+      mock_suggestions_callback,
+      Run(Property(&Status::IsSuccess, true), GURL(kFromURL),
+          Pointee(ElementsAre(AllOf(
+              Property(&ContentSuggestion::id,
+                       Property(&ContentSuggestion::ID::category,
+                                Category::FromKnownCategory(
+                                    KnownCategories::CONTEXTUAL))),
+              Property(&ContentSuggestion::url, GURL(kSuggestionURL)))))));
+  source()->FetchContextualSuggestions(
+      GURL(kFromURL), mock_suggestions_callback.ToOnceCallback());
+  base::RunLoop().RunUntilIdle();
+}
+
+}  // namespace ntp_snippets