Initial implementation of FeatureList in base/.

base/metrics/feature_list_unittest.cc

Index: base/metrics/feature_list_unittest.cc
diff --git a/base/metrics/feature_list_unittest.cc b/base/metrics/feature_list_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..29a46d612357e804cb1a02cee40e3629c229effd
--- /dev/null
+++ b/base/metrics/feature_list_unittest.cc
@@ -0,0 +1,96 @@
+// Copyright 2015 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 "base/metrics/feature_list.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+namespace {
+
+const char kFeatureOnName[] = "Example1";
+struct Feature kExampleFeatureOn {
+  kFeatureOnName, true
+};
+
+const char kFeatureOffName[] = "Example2";
+struct Feature kExampleFeatureOff {
+  kFeatureOffName, false
+};
+
+class FeatureListTest : public testing::Test {
+ public:
+  FeatureListTest() : feature_list_(new FeatureList) {
+    RegisterFeatureListInstance();
+  }
+  ~FeatureListTest() override { ClearFeatureListInstance(); }
+
+  void RegisterFeatureListInstance() {
+    FeatureList::SetInstance(make_scoped_ptr(feature_list_));
+  }
+  void ClearFeatureListInstance() { FeatureList::ClearInstanceForTesting(); }
+
+  FeatureList* feature_list() { return feature_list_; }
+
+ private:
+  // Weak. Owned by the FeatureList::SetInstance().
+  FeatureList* feature_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(FeatureListTest);
+};
+
+}  // namespace
+
+TEST_F(FeatureListTest, DefaultStates) {
+  EXPECT_TRUE(FeatureList::IsEnabled(kExampleFeatureOn));
+  EXPECT_FALSE(FeatureList::IsEnabled(kExampleFeatureOff));
+}
+
+TEST_F(FeatureListTest, InitializeFromCommandLine) {
+  struct {
+    const char* enable_features;
+    const char* disable_features;
+    bool expected_feature_on_state;
+    bool expected_feature_off_state;
+  } test_cases[] = {
+      {"", "", true, false},
+      {"Example2", "", true, true},
+      {"Example2", "Example1", false, true},
+      {"Example1,Example2", "", true, true},
+      {"", "Example1,Example2", false, false},
+      // In the case an entry is both, disable takes precedence.
+      {"Example1", "Example1,Example2", false, false},
+  };
+
+  for (size_t i = 0; i < arraysize(test_cases); i++) {
+    const auto& test_case = test_cases[i];
+
+    FeatureList feature_list;
+    feature_list.InitializeFromCommandLine(test_case.enable_features,
+                                           test_case.disable_features);
+    feature_list.FinalizeInitialization();
+
+    EXPECT_EQ(test_case.expected_feature_on_state,
+              feature_list.IsFeatureEnabled(kExampleFeatureOn))
+        << i;
+    EXPECT_EQ(test_case.expected_feature_off_state,
+              feature_list.IsFeatureEnabled(kExampleFeatureOff))
+        << i;
+  }
+}
+
+TEST_F(FeatureListTest, CheckFeatureIdentity) {
+  EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kExampleFeatureOn));
+  EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kExampleFeatureOn));
+  EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kExampleFeatureOff));
+  EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kExampleFeatureOff));
+
+  struct Feature kExampleFeatureOn2 {
+    kFeatureOnName, true
+  };
+  EXPECT_FALSE(feature_list()->CheckFeatureIdentity(kExampleFeatureOn2));
+}
+
+}  // namespace base