1 // Copyright 2023 The Chromium Authors
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/strings/to_string.h"
6
7 #include <ios>
8 #include <ostream>
9 #include <string>
10
11 #include "testing/gtest/include/gtest/gtest.h"
12
13 namespace base {
14 namespace {
15
TEST(ToStringTest,Streamable)16 TEST(ToStringTest, Streamable) {
17 // Types with built-in <<.
18 EXPECT_EQ(ToString("foo"), "foo");
19 EXPECT_EQ(ToString(123), "123");
20 }
21
22 enum class StreamableTestEnum { kGreeting, kLocation };
23
operator <<(std::ostream & os,const StreamableTestEnum & value)24 std::ostream& operator<<(std::ostream& os, const StreamableTestEnum& value) {
25 switch (value) {
26 case StreamableTestEnum::kGreeting:
27 return os << "hello";
28 case StreamableTestEnum::kLocation:
29 return os << "world";
30 }
31 }
32
TEST(ToStringTest,UserDefinedStreamable)33 TEST(ToStringTest, UserDefinedStreamable) {
34 // Type with user-defined <<.
35 EXPECT_EQ(ToString(StreamableTestEnum::kGreeting), "hello");
36 EXPECT_EQ(ToString(StreamableTestEnum::kGreeting, " ",
37 StreamableTestEnum::kLocation),
38 "hello world");
39 }
40
41 class HasToString {
42 public:
ToString() const43 std::string ToString() const { return "yay!"; }
44 };
45
TEST(ToStringTest,UserDefinedToString)46 TEST(ToStringTest, UserDefinedToString) {
47 // Type with user-defined ToString().
48 EXPECT_EQ(ToString(HasToString()), "yay!");
49 }
50
51 class UnusualToString {
52 public:
ToString() const53 HasToString ToString() const { return HasToString(); }
54 };
55
TEST(ToStringTest,ToStringReturnsNonStdString)56 TEST(ToStringTest, ToStringReturnsNonStdString) {
57 // Types with a ToString() that does not directly return a std::string should
58 // still work.
59 EXPECT_EQ(ToString(UnusualToString()), "yay!");
60 }
61
62 enum class NonStreamableTestEnum { kGreeting = 0, kLocation };
63
TEST(ToStringTest,ScopedEnum)64 TEST(ToStringTest, ScopedEnum) {
65 // Scoped enums without a defined << should print as their underlying type.
66 EXPECT_EQ(ToString(NonStreamableTestEnum::kLocation), "1");
67 }
68
TEST(ToStringTest,IoManip)69 TEST(ToStringTest, IoManip) {
70 // I/O manipulators should have their expected effect, not be printed as
71 // function pointers.
72 EXPECT_EQ(ToString("42 in hex is ", std::hex, 42), "42 in hex is 2a");
73 }
74
Func()75 void Func() {}
76
TEST(ToStringTest,FunctionPointer)77 TEST(ToStringTest, FunctionPointer) {
78 // We don't care about the actual address, but a function pointer should not
79 // be implicitly converted to bool.
80 EXPECT_NE(ToString(&Func), ToString(true));
81
82 // Functions should be treated like function pointers.
83 EXPECT_EQ(ToString(Func), ToString(&Func));
84 }
85
86 class NotStringifiable {};
87
88 class OverloadsAddressOp {
89 public:
operator &()90 OverloadsAddressOp* operator&() { return nullptr; }
operator &() const91 const OverloadsAddressOp* operator&() const { return nullptr; }
92 };
93
TEST(ToStringTest,NonStringifiable)94 TEST(ToStringTest, NonStringifiable) {
95 // Non-stringifiable types should be printed using a fallback.
96 EXPECT_NE(ToString(NotStringifiable()).find("-byte object at 0x"),
97 std::string::npos);
98
99 // Non-stringifiable types which overload operator& should print their real
100 // address.
101 EXPECT_NE(ToString(OverloadsAddressOp()),
102 ToString(static_cast<OverloadsAddressOp*>(nullptr)));
103 }
104
105 } // namespace
106 } // namespace base
107