Migrate --enable-arc and --arc-available part 1.

components/arc/arc_util_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/arc/arc_util.h"
+
+#include <memory>
+
+#include "base/command_line.h"
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "base/test/scoped_command_line.h"
+#include "base/test/scoped_feature_list.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace arc {
+
+class ArcUtilTest : public testing::Test {

[Yusuke Sato, 2017/01/24 19:02:44]

nit: put this in an anonymous namespace

[hidehiko, 2017/01/25 17:54:47]

Can I keep it as is for consistency?
IIUC, most of ARC test fixture class are directly under the arc namespace.

[Yusuke Sato, 2017/01/25 18:59:31]

Should we keep doing that?

https://google.github.io/styleguide/cppguide.html#Unnamed_Namespaces_and_Stat...
does not exclude _test.cc files.

[hidehiko, 2017/01/26 02:36:59]

I see. So,
- done in this file only.
- other tests under arc/, let's do it separately. Tracking bug: crbug.com/685464

+ public:
+  ArcUtilTest() = default;
+  ~ArcUtilTest() override = default;
+
+  void SetUp() override {
+    scoped_command_line_ = base::MakeUnique<base::test::ScopedCommandLine>();
+  }
+
+  void TearDown() override { scoped_command_line_.reset(); }
+
+ private:
+  std::unique_ptr<base::test::ScopedCommandLine> scoped_command_line_;

[hidehiko, 2017/01/25 17:54:47]

Note: it turned out that test framework actually restores command line flags per
test case, so we do not need it.

+
+  DISALLOW_COPY_AND_ASSIGN(ArcUtilTest);
+};
+
+// Test --arc-available with EnableARC feature combination.
+TEST_F(ArcUtilTest, IsArcAvailable_Installed) {

[Yusuke Sato, 2017/01/24 19:02:44]

nit: is it common to have underscores in a test name?

[hidehiko, 2017/01/25 17:54:47]

I think yes.
https://cs.chromium.org/search/?q=TEST_F%5C(.%2B_&sq=package:chromium&type=cs

about 1200 hits. Many are MAYBE_ and DISABLED_, but it actually contains real
'_' usages.

+  auto* command_line = base::CommandLine::ForCurrentProcess();
+
+  // If ARC is not installed, IsArcAvailable() should return false,
+  // regardless of EnableARC feature.
+  command_line->InitFromArgv({""});
+
+  // Not availble, by-default.
+  EXPECT_FALSE(IsArcAvailable());
+
+  {
+    base::test::ScopedFeatureList feature_list;
+    feature_list.InitFromCommandLine("EnableARC", "");

[Yusuke Sato, 2017/01/24 19:02:44]

* kEnableARC[] please.
* Most of us are not familiar with ScopedFeatureList. A comment like '// Enable
the experiment.' would help.

[hidehiko, 2017/01/25 17:54:47]

Instead, I introduced a small wrapper. WDYT?

+    EXPECT_FALSE(IsArcAvailable());
+  }
+  {
+    base::test::ScopedFeatureList feature_list;
+    feature_list.InitFromCommandLine("", "EnableARC");

[Yusuke Sato, 2017/01/24 19:02:44]

// Disable the experiment.

(here and elsewhere)

[hidehiko, 2017/01/25 17:54:47]

Acknowledged.

+    EXPECT_FALSE(IsArcAvailable());
+  }
+
+  // If ARC is installed, IsArcAvailable() should return true when EnableARC
+  // feature is set.
+  command_line->InitFromArgv({"", "--arc-available"});
+
+  // Not available, by-default, too.
+  EXPECT_FALSE(IsArcAvailable());
+
+  {
+    base::test::ScopedFeatureList feature_list;
+    feature_list.InitFromCommandLine("EnableARC", "");
+    EXPECT_TRUE(IsArcAvailable());
+  }
+  {
+    base::test::ScopedFeatureList feature_list;
+    feature_list.InitFromCommandLine("", "EnableARC");
+    EXPECT_FALSE(IsArcAvailable());
+  }
+}
+
+TEST_F(ArcUtilTest, IsArcAvailable_OfficialSupport) {

[Yusuke Sato, 2017/01/24 19:02:44]

same

[hidehiko, 2017/01/25 17:54:47]

Acknowledged.

+  // Regardless of FeatureList, IsArcAvailable() should return true.
+  auto* command_line = base::CommandLine::ForCurrentProcess();
+  command_line->InitFromArgv({"", "--enable-arc"});
+  EXPECT_TRUE(IsArcAvailable());
+}
+
+}  // namespace arc