Add a unittest for image_data_fetcher

components/image_fetcher/image_data_fetcher_unittest.cc

+// Copyright 2016 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/image_fetcher/image_data_fetcher.h"
+
+#include <memory>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
+#include "net/url_request/test_url_fetcher_factory.h"
+#include "net/url_request/url_request_status.h"
+#include "net/url_request/url_request_test_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+const GURL kImageURL("http://www.example.com/image1");

[Bernhard Bauer, 2016/06/20 17:28:38]

This will still create a static initializer. The only things allowed are basic
data types (int, char, etc.) and pointers to and arrays thereof.

[markusheintz_, 2016/06/21 15:56:08]

sry forgot. Done

+const char kURLResponseData[] = "EncodedImageData";
+
+}  // namespace
+
+namespace image_fetcher {
+
+class ImageDataFetcherTest : public testing::Test {
+ public:
+  ImageDataFetcherTest()
+      : message_loop_(),
+        test_request_context_getter_(
+            new net::TestURLRequestContextGetter(message_loop_.task_runner())),
+        image_data_fetcher_(test_request_context_getter_.get()),
+        num_callbacks_run_(0) {}
+  ~ImageDataFetcherTest() override {}
+
+  // Callback that is called by the FetchImageData test.
+  void OnImageDataFetched(const std::string& image_data) {
+    EXPECT_EQ(std::string(kURLResponseData), image_data);
+  }
+
+  // Callback that is called by the FetchImageData_FailedRequest test.
+  void OnImageDataFetchedFailedRequest(const std::string& image_data) {
+    EXPECT_EQ(std::string(), image_data);
+  }
+
+  // Callback that is called by the FetchImageData_MultipleRequests test.
+  void OnImageDataFetchedMultipleRequests(const std::string& image_data) {
+    ++num_callbacks_run_;
+  }
+
+ protected:
+  base::MessageLoop message_loop_;
+
+  scoped_refptr<net::URLRequestContextGetter> test_request_context_getter_;
+
+  ImageDataFetcher image_data_fetcher_;
+
+  net::TestURLFetcherFactory fetcher_factory_;
+
+  // The number of times the OnImageDataFetchedMultipleRequests callback was
+  // called during a test run.
+  int num_callbacks_run_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ImageDataFetcherTest);
+};
+
+TEST_F(ImageDataFetcherTest, FetchImageData) {
+  image_data_fetcher_.FetchImageData(
+      kImageURL,
+      base::Bind(&ImageDataFetcherTest::OnImageDataFetched,
+                 base::Unretained(this)a));

[Bernhard Bauer, 2016/06/20 17:28:38]

typo?

[markusheintz_, 2016/06/21 15:56:08]

Done.

+
+  // Get and configure the TestURLFetcher.
+  net::TestURLFetcher* test_url_fetcher = fetcher_factory_.GetFetcherByID(0);
+  ASSERT_NE(nullptr, test_url_fetcher);
+  test_url_fetcher->set_status(
+      net::URLRequestStatus(net::URLRequestStatus::SUCCESS, net::OK));
+  test_url_fetcher->SetResponseString(std::string(kURLResponseData));

[Bernhard Bauer, 2016/06/20 17:28:38]

std::string has an implicit constructor that takes a char*, so you don't need to
call it explicitly.

[markusheintz_, 2016/06/21 15:56:08]

Done.

+
+  // Call the URLFetcher delegate to continue the test.
+  test_url_fetcher->delegate()->OnURLFetchComplete(test_url_fetcher);
+}
+
+TEST_F(ImageDataFetcherTest, FetchImageData_FailedRequest) {
+  image_data_fetcher_.FetchImageData(
+      kImageURL,
+      base::Bind(&ImageDataFetcherTest::OnImageDataFetchedFailedRequest,
+                 base::Unretained(this)));
+
+  // Get and configure the TestURLFetcher.
+  net::TestURLFetcher* test_url_fetcher = fetcher_factory_.GetFetcherByID(0);
+  ASSERT_NE(nullptr, test_url_fetcher);
+  test_url_fetcher->set_status(
+      net::URLRequestStatus(net::URLRequestStatus::FAILED,
+                            net::ERR_INVALID_URL));
+
+  // Call the URLFetcher delegate to continue the test.
+  test_url_fetcher->delegate()->OnURLFetchComplete(test_url_fetcher);
+}
+
+TEST_F(ImageDataFetcherTest, FetchImageData_MultipleRequests) {
+  ImageDataFetcher::ImageDataFetcherCallback callback1 =
+      base::Bind(&ImageDataFetcherTest::OnImageDataFetchedMultipleRequests,
+                 base::Unretained(this));
+  ImageDataFetcher::ImageDataFetcherCallback callback2 =
+      base::Bind(&ImageDataFetcherTest::OnImageDataFetchedMultipleRequests,
+                 base::Unretained(this));
+
+  image_data_fetcher_.FetchImageData(kImageURL, callback1);
+  image_data_fetcher_.FetchImageData(kImageURL, callback2);
+
+  // Multiple calls to the FetchImageData for the same URL will result in

[Bernhard Bauer, 2016/06/20 17:28:38]

No "the" before FetchImageData

[markusheintz_, 2016/06/21 15:56:08]

Done.

+  // multiple URLFetcher beeing created.

[Marc Treib, 2016/06/20 15:21:42]

nit: being

[Bernhard Bauer, 2016/06/20 17:28:38]

URLFetchers

[markusheintz_, 2016/06/21 15:56:08]

Done.

[markusheintz_, 2016/06/21 15:56:08]

Done.

+  net::TestURLFetcher* test_url_fetcher = fetcher_factory_.GetFetcherByID(0);
+  ASSERT_NE(nullptr, test_url_fetcher);
+  test_url_fetcher->delegate()->OnURLFetchComplete(test_url_fetcher);
+
+  test_url_fetcher = fetcher_factory_.GetFetcherByID(1);
+  ASSERT_NE(nullptr, test_url_fetcher);
+  test_url_fetcher->delegate()->OnURLFetchComplete(test_url_fetcher);
+
+  EXPECT_EQ(num_callbacks_run_, 2);
+}
+
+}  // namespace image_fetcher