1 // Copyright 2020 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/ranges/ranges.h"
6
7 #include <array>
8 #include <initializer_list>
9 #include <vector>
10
11 #include "testing/gtest/include/gtest/gtest.h"
12
13 namespace base {
14
15 namespace {
16
17 // Test struct with free function overloads for begin and end. Tests whether the
18 // free functions are found.
19 struct S {
20 std::vector<int> v;
21 };
22
begin(const S & s)23 auto begin(const S& s) {
24 return s.v.begin();
25 }
26
end(const S & s)27 auto end(const S& s) {
28 return s.v.end();
29 }
30
31 // Test struct with both member and free function overloads for begin and end.
32 // Tests whether the member function is preferred.
33 struct T {
beginbase::__anon1d0002f10111::T34 constexpr int begin() const { return 1; }
endbase::__anon1d0002f10111::T35 constexpr int end() const { return 1; }
36 };
37
begin(const T & t)38 constexpr int begin(const T& t) {
39 return 2;
40 }
41
end(const T & t)42 constexpr int end(const T& t) {
43 return 2;
44 }
45
46 // constexpr utility to generate a std::array. Ensures that a mutable array can
47 // be used in a constexpr context.
48 template <size_t N>
GenerateArray()49 constexpr std::array<int, N> GenerateArray() {
50 std::array<int, N> arr{};
51 int i = 0;
52 for (auto* it = ranges::begin(arr); it != ranges::end(arr); ++it) {
53 *it = i++;
54 }
55
56 return arr;
57 }
58
59 } // namespace
60
TEST(RangesTest,BeginPrefersMember)61 TEST(RangesTest, BeginPrefersMember) {
62 constexpr T t;
63 static_assert(ranges::begin(t) == 1, "");
64 }
65
TEST(RangesTest,BeginConstexprContainers)66 TEST(RangesTest, BeginConstexprContainers) {
67 int arr[1]{};
68 static_assert(arr == ranges::begin(arr), "");
69
70 static constexpr std::initializer_list<int> il = {1, 2, 3};
71 static_assert(il.begin() == ranges::begin(il), "");
72
73 static constexpr std::array<int, 3> array = {1, 2, 3};
74 static_assert(&array[0] == ranges::begin(array), "");
75 }
76
TEST(RangesTest,BeginRegularContainers)77 TEST(RangesTest, BeginRegularContainers) {
78 std::vector<int> vec;
79 S s;
80
81 EXPECT_EQ(vec.begin(), ranges::begin(vec));
82 EXPECT_EQ(s.v.begin(), ranges::begin(s));
83 }
84
TEST(RangesTest,EndPrefersMember)85 TEST(RangesTest, EndPrefersMember) {
86 constexpr T t;
87 static_assert(ranges::end(t) == 1, "");
88 }
89
TEST(RangesTest,EndConstexprContainers)90 TEST(RangesTest, EndConstexprContainers) {
91 int arr[1]{};
92 static_assert(arr + 1 == ranges::end(arr), "");
93
94 static constexpr std::initializer_list<int> il = {1, 2, 3};
95 static_assert(il.end() == ranges::end(il), "");
96
97 static constexpr std::array<int, 3> array = {1, 2, 3};
98 static_assert(&array[0] + 3 == ranges::end(array), "");
99 }
100
TEST(RangesTest,EndRegularContainers)101 TEST(RangesTest, EndRegularContainers) {
102 std::vector<int> vec;
103 S s;
104
105 EXPECT_EQ(vec.end(), ranges::end(vec));
106 EXPECT_EQ(s.v.end(), ranges::end(s));
107 }
108
TEST(RangesTest,BeginEndStdArray)109 TEST(RangesTest, BeginEndStdArray) {
110 static constexpr std::array<int, 0> null_array = GenerateArray<0>();
111 static_assert(ranges::begin(null_array) == ranges::end(null_array), "");
112
113 static constexpr std::array<int, 3> array = GenerateArray<3>();
114 static_assert(array[0] == 0, "");
115 static_assert(array[1] == 1, "");
116 static_assert(array[2] == 2, "");
117 }
118
119 } // namespace base
120