Support Using ScopedFeatureList in BrowserTest

chrome/test/base/in_process_browser_test_browsertest.cc

 // Copyright (c) 2011 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 <stddef.h>
 #include <string.h>
 
+#include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/macros.h"
 #include "base/path_service.h"
+#include "base/strings/string_split.h"
+#include "base/test/scoped_feature_list.h"
 #include "chrome/browser/after_startup_task_utils.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "content/public/common/content_switches.h"
 #include "net/base/filename_util.h"
 #include "net/base/net_errors.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 class InProcessBrowserTestP
     : public InProcessBrowserTest,
       public ::testing::WithParamInterface<const char*> {
 };
@@ skipping 113 matching lines @@
     InProcessAccessibilityBrowserTest, VerifyAccessibilityFail) {
   ASSERT_TRUE(NavigateToURL(kFailHTML));
 
   std::string test_result;
   EXPECT_FALSE(RunAccessibilityChecks(&test_result));
 
   // Error should NOT be empty on failure.
   EXPECT_NE("", test_result);
 }
 
+const base::Feature kTestFeatureForBrowserTest{
+    "TestFeatureForBrowserTest", base::FEATURE_DISABLED_BY_DEFAULT};
+
+class BrowserTestScopedFeatureListTest : public InProcessBrowserTest {
+ public:
+  void SetUp() override {
+    std::string disabled_features;
+    base::FeatureList::GetInstance()->GetFeatureOverrides(&enabled_features_,
+                                                          &disabled_features);
+    scoped_feature_list_.InitAndEnableFeature(kTestFeatureForBrowserTest);
+    InProcessBrowserTest::SetUp();
+  }
+
+  std::string enabled_features_;
+
+ private:
+  base::test::ScopedFeatureList scoped_feature_list_;
+};
+
+IN_PROC_BROWSER_TEST_F(BrowserTestScopedFeatureListTest, FeatureListTest) {
+  std::string enabled_features0;
+  std::string disabled_features0;
+
+  base::FeatureList::GetInstance()->GetFeatureOverrides(&enabled_features0,
+                                                        &disabled_features0);
+
+  base::StringPiece enabled_features = enabled_features0;
+
+  // Ensure we repected the features from command line.
+  std::vector<base::StringPiece> original_enabled_features =
+      base::SplitStringPiece(enabled_features_, ",", base::TRIM_WHITESPACE,
+                             base::SPLIT_WANT_NONEMPTY);
+
+  for (base::StringPiece enabled_feature : original_enabled_features) {
+    EXPECT_NE(enabled_features.find(enabled_feature), base::StringPiece::npos);
+  }
+
+  // Ensure kTestFeatureForBrowserTest enabled.
+  EXPECT_TRUE(base::FeatureList::IsEnabled(kTestFeatureForBrowserTest));

[Ilya Sherman, 2017/06/13 22:42:48]

IMO this part of the test is useful.  The EXPECT_NE in the loop above is not as
useful, since this test doesn't actually control what features are
enabled/disabled prior to the test; and it might in fact be the empty set.  It
certainly doesn't make much sense to test *only* the enabled features, and not
the disabled features as well.  We should either test both or neither.

[chaopeng, 2017/06/28 14:16:51]

Done.

+}
+
 }  // namespace