Add a unit test for the update file path task.

Bug: 758733
Change-Id: I0b4cac2f3bc605383e835184ef7c27c51be1be4a
Reviewed-on: https://chromium-review.googlesource.com/994144
Commit-Queue: Peter Williamson <petewil@chromium.org>
Reviewed-by: Yafei Duan <romax@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548240}

components/offline_pages/core/BUILD.gn

@@ -170,6 +170,7 @@ source_set("unit_tests") {
     "model/start_offline_page_upgrade_task_unittest.cc",
     "model/startup_maintenance_task_unittest.cc",
     "model/store_thumbnail_task_unittest.cc",
+    "model/update_file_path_task_unittest.cc",
     "offline_event_logger_unittest.cc",
     "offline_page_archiver_unittest.cc",
     "offline_page_feature_unittest.cc",

components/offline_pages/core/model/update_file_path_task_unittest.cc

+// Copyright 2018 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/offline_pages/core/model/update_file_path_task.h"
+
+#include <memory>
+
+#include "base/files/file_path.h"
+#include "components/offline_pages/core/model/model_task_test_base.h"
+#include "components/offline_pages/core/model/offline_page_item_generator.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace offline_pages {
+
+namespace {
+
+// Callback to check results of task.
+class UpdateFilePathTaskTestCallback {
+ public:
+  UpdateFilePathTaskTestCallback()
+      : called_(false), success_(false), weak_ptr_factory_(this) {}
+
+  bool called() const { return called_; }
+
+  bool success() const { return success_; }
+
+  void Run(bool success) {
+    called_ = true;
+    success_ = success;
+  }
+
+  base::WeakPtr<UpdateFilePathTaskTestCallback> GetWeakPtr() {
+    return weak_ptr_factory_.GetWeakPtr();
+  }
+
+ private:
+  bool called_;
+  bool success_;
+  base::WeakPtrFactory<UpdateFilePathTaskTestCallback> weak_ptr_factory_;
+};
+}  // namespace
+
+class UpdateFilePathTaskTest : public ModelTaskTestBase {};
+
+TEST_F(UpdateFilePathTaskTest, UpdateFilePath) {
+  OfflinePageItem page = generator()->CreateItem();
+  store_test_util()->InsertItem(page);
+  base::FilePath new_file_path(FILE_PATH_LITERAL("/new/path/to/file"));
+  UpdateFilePathTaskTestCallback done_callback;
+
+  // Build and run a task to change the file path in the offline page model.
+  auto task = std::make_unique<UpdateFilePathTask>(
+      store(), page.offline_id, new_file_path,
+      base::BindOnce(&UpdateFilePathTaskTestCallback::Run,
+                     done_callback.GetWeakPtr()));
+  RunTask(std::move(task));
+
+  auto offline_page = store_test_util()->GetPageByOfflineId(page.offline_id);
+
+  EXPECT_EQ(new_file_path, offline_page->file_path);
+  EXPECT_TRUE(done_callback.called());
+  EXPECT_TRUE(done_callback.success());
+}
+
+}  // namespace offline_pages