+/*
+ * Copyright 2017 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <folly/container/Access.h>
+
+#include <array>
+#include <initializer_list>
+#include <vector>
+
+#include <folly/portability/GTest.h>
+
+class AccessTest : public testing::Test {};
+
+TEST_F(AccessTest, size_vector) {
+ EXPECT_EQ(3, folly::size(std::vector<int>{1, 2, 3}));
+}
+
+TEST_F(AccessTest, size_array) {
+ constexpr auto const a = std::array<int, 3>{{1, 2, 3}};
+ constexpr auto const size = folly::size(a);
+ EXPECT_EQ(3, size);
+}
+
+TEST_F(AccessTest, size_carray) {
+ constexpr int const a[3] = {1, 2, 3};
+ constexpr auto const size = folly::size(a);
+ EXPECT_EQ(3, size);
+}
+
+TEST_F(AccessTest, size_initializer_list) {
+ EXPECT_EQ(3, folly::size({1, 2, 3}));
+ EXPECT_EQ(3, folly::size(std::initializer_list<int>{1, 2, 3}));
+}
+
+TEST_F(AccessTest, empty_vector) {
+ EXPECT_FALSE(folly::empty(std::vector<int>{1, 2, 3}));
+ EXPECT_TRUE(folly::empty(std::vector<int>{}));
+}
+
+TEST_F(AccessTest, empty_array) {
+ {
+ constexpr auto const a = std::array<int, 3>{{1, 2, 3}};
+ constexpr auto const empty = folly::empty(a);
+ EXPECT_FALSE(empty);
+ }
+ {
+ constexpr auto const a = std::array<int, 0>{{}};
+ constexpr auto const empty = folly::empty(a);
+ EXPECT_TRUE(empty);
+ }
+}
+
+TEST_F(AccessTest, empty_carray) {
+ constexpr int const a[3] = {1, 2, 3};
+ constexpr auto const empty = folly::empty(a);
+ EXPECT_FALSE(empty);
+ // zero-length arrays are not allowed in the language
+}
+
+TEST_F(AccessTest, empty_initializer_list) {
+ EXPECT_FALSE(folly::empty({1, 2, 3}));
+ EXPECT_FALSE(folly::empty(std::initializer_list<int>{1, 2, 3}));
+ EXPECT_TRUE(folly::empty(std::initializer_list<int>{}));
+}
+
+TEST_F(AccessTest, data_vector) {
+ EXPECT_EQ(1, *folly::data(std::vector<int>{1, 2, 3}));
+ auto v = std::vector<int>{1, 2, 3};
+ *folly::data(v) = 4;
+ EXPECT_EQ(4, v[0]);
+}
+
+TEST_F(AccessTest, data_array) {
+ constexpr auto const a = std::array<int, 3>{{1, 2, 3}};
+ auto const data = folly::data(a); // not constexpr until C++17
+ EXPECT_EQ(1, *data);
+}
+
+TEST_F(AccessTest, data_carray) {
+ constexpr int const a[3] = {1, 2, 3};
+ auto const data = folly::data(a); // not constexpr until C++17
+ EXPECT_EQ(1, *data);
+}
+
+TEST_F(AccessTest, data_initializer_list) {
+ EXPECT_EQ(1, *folly::data({1, 2, 3}));
+ EXPECT_EQ(1, *folly::data(std::initializer_list<int>{1, 2, 3}));
+}