Create the BackgroundFetchBatchManager and initiate a download.

content/browser/background_fetch/background_fetch_batch_manager_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 "content/browser/background_fetch/background_fetch_batch_manager.h"
+
+#include "base/bind_helpers.h"
+#include "base/callback_helpers.h"
+#include "base/run_loop.h"
+#include "content/browser/background_fetch/background_fetch_data_manager.h"
+#include "content/browser/background_fetch/batch_request.h"
+#include "content/browser/background_fetch/fetch_request.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/test/mock_download_manager.h"
+#include "content/public/test/test_browser_context.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+const char kOrigin[] = "https://example.com/";
+const char kBatchGuid[] = "TestRequestGuid";
+constexpr int64_t kServiceWorkerRegistrationId = 9001;
+const char kTestUrl[] = "http://www.example.com/example.html";
+const char kTag[] = "testTag";
+
+}  // namespace
+
+namespace content {
+
+class BackgroundFetchBatchManagerTest : public ::testing::Test {
+ public:
+  BackgroundFetchBatchManagerTest()
+      : batch_manager_(
+            &browser_context_,
+            BrowserContext::GetDefaultStoragePartition(&browser_context_)),
+        download_manager_(new MockDownloadManager()) {
+    BrowserContext::SetDownloadManagerForTesting(&browser_context_,
+                                                 download_manager_);

[Peter Beverloo, 2017/02/24 02:05:15]

Something to consider --

We usually set overrides like this in a method called SetUp() which is called by
the testing framework. (Like TearDown().)

This is not super important for unit tests, but it is for browser tests. They
usually inherit from intermediate testing classes that provide other bits of
functionality, such as ContentBrowserTest. There ordering matters.

In effect, we try to be consistent to minimize the possibility of forgetting to
do this in the right order. It has certainly bit me in the past.

[harkness, 2017/02/24 11:47:10]

Sounds like a good practice to keep to. I've moved it.

+  }
+  ~BackgroundFetchBatchManagerTest() override {}

[Peter Beverloo, 2017/02/24 02:05:15]

nit: "= default" all the things

[harkness, 2017/02/24 11:47:10]

Done.

+
+  void ProcessBatch(const std::string& batch_guid,
+                    BackgroundFetchDataManager::BatchData* batch_data) {
+    base::RunLoop run_loop;
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        base::Bind(&BackgroundFetchBatchManagerTest::ProcessBatchOnIO,
+                   base::Unretained(this), batch_guid, batch_data,
+                   run_loop.QuitClosure()));
+    run_loop.Run();
+  }
+
+  void ProcessBatchOnIO(const std::string& batch_guid,
+                        BackgroundFetchDataManager::BatchData* batch_data,
+                        const base::Closure& closure) {
+    batch_manager_.ProcessBatch(batch_guid, batch_data);
+    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, closure);
+  }
+
+  BackgroundFetchBatchManager* batch_manager() { return &batch_manager_; }
+  MockDownloadManager* download_manager() { return download_manager_; }
+
+ private:
+  TestBrowserThreadBundle thread_bundle_;
+  TestBrowserContext browser_context_;
+  BackgroundFetchBatchManager batch_manager_;
+  MockDownloadManager* download_manager_;

[Peter Beverloo, 2017/02/24 02:05:15]

This needs to be an std::unique_ptr<>. We leak the instance now.

[harkness, 2017/02/24 11:47:10]

Actually, I believe that we want to pass the raw pointer to the
SetDownloadManagerForTesting call, then the BrowserContext calls WrapUnique on
it. The important thing is that the DownloadManager needs to outlive the test.
I'll comment that in the code.

+};
+
+TEST_F(BackgroundFetchBatchManagerTest, StartDownload) {
+  BatchRequest batch_request(kTag, url::Origin(GURL(kOrigin)),
+                             kServiceWorkerRegistrationId);
+  FetchRequest fetch_request(GURL(kTestUrl), kBatchGuid);
+  std::vector<FetchRequest> fetch_requests;
+  fetch_requests.push_back(fetch_request);

[Peter Beverloo, 2017/02/24 02:05:15]

nit:

std::vector<FetchRequest> fetch_requests { fetch_request };

[harkness, 2017/02/24 11:47:10]

Done.

+
+  // Get a BatchData to give to the BatchManager. The BatchManager then gets the
+  // FetchRequests from the BatchData.
+  BackgroundFetchDataManager::BatchData batch_data(batch_request,
+                                                   fetch_requests);
+
+  EXPECT_CALL(*(download_manager()),
+              DownloadUrlMock(::testing::Pointee(::testing::Property(
+                  &DownloadUrlParameters::url, GURL(kTestUrl)))))
+      .Times(1);
+
+  ProcessBatch(kBatchGuid, &batch_data);
+}
+
+}  // namespace content