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base / strings / to_string_unittest.cc [blame]
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/strings/to_string.h"
#include <ios>
#include <ostream>
#include <string>
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace {
class NotStringifiable {};
class HasToString {
public:
std::string ToString() const { return "yay!"; }
};
// .ToString() support on structs.
static_assert(!internal::SupportsToString<NotStringifiable>,
"value without ToString() shouldn't be marked SupportsToString");
static_assert(!internal::SupportsToString<NotStringifiable&>,
"& without ToString() shouldn't be marked SupportsToString");
static_assert(!internal::SupportsToString<const NotStringifiable&>,
"const& without ToString() shouldn't be marked SupportsToString");
static_assert(!internal::SupportsToString<NotStringifiable&&>,
"&& without ToString() shouldn't be marked SupportsToString");
static_assert(internal::SupportsToString<HasToString>,
"value with ToString() should be marked SupportsToString");
static_assert(internal::SupportsToString<HasToString&>,
"& with ToString() should be marked SupportsToString");
static_assert(internal::SupportsToString<const HasToString&>,
"const& with ToString() should be marked SupportsToString");
static_assert(internal::SupportsToString<HasToString&&>,
"&& with ToString() should be marked SupportsToString");
TEST(ToStringTest, Streamable) {
// Types with built-in <<.
EXPECT_EQ(ToString("foo"), "foo");
EXPECT_EQ(ToString(123), "123");
}
enum class StreamableTestEnum { kGreeting, kLocation };
std::ostream& operator<<(std::ostream& os, const StreamableTestEnum& value) {
switch (value) {
case StreamableTestEnum::kGreeting:
return os << "hello";
case StreamableTestEnum::kLocation:
return os << "world";
}
}
TEST(ToStringTest, UserDefinedStreamable) {
// Type with user-defined <<.
EXPECT_EQ(ToString(StreamableTestEnum::kGreeting), "hello");
EXPECT_EQ(ToString(StreamableTestEnum::kGreeting, " ",
StreamableTestEnum::kLocation),
"hello world");
}
TEST(ToStringTest, UserDefinedToString) {
// Type with user-defined ToString().
EXPECT_EQ(ToString(HasToString()), "yay!");
}
class UnusualToString {
public:
HasToString ToString() const { return HasToString(); }
};
TEST(ToStringTest, ToStringReturnsNonStdString) {
// Types with a ToString() that does not directly return a std::string should
// still work.
EXPECT_EQ(ToString(UnusualToString()), "yay!");
}
enum class NonStreamableTestEnum { kGreeting = 0, kLocation };
TEST(ToStringTest, ScopedEnum) {
// Scoped enums without a defined << should print as their underlying type.
EXPECT_EQ(ToString(NonStreamableTestEnum::kLocation), "1");
}
TEST(ToStringTest, WideChars) {
EXPECT_EQ(ToString(u'a'), "97");
EXPECT_EQ(ToString(L'a'), "97");
}
TEST(ToStringTest, IoManip) {
// I/O manipulators should have their expected effect, not be printed as
// function pointers.
EXPECT_EQ(ToString("42 in hex is ", std::hex, 42), "42 in hex is 2a");
}
TEST(ToStringTest, Tuple) {
// Tuples should correctly format the contained types.
EXPECT_EQ(ToString(std::make_tuple(StreamableTestEnum::kGreeting,
HasToString(), "a string")),
"<hello, yay!, a string>");
}
void Func() {}
TEST(ToStringTest, FunctionPointer) {
// We don't care about the actual address, but a function pointer should not
// be implicitly converted to bool.
EXPECT_NE(ToString(&Func), ToString(true));
// Functions should be treated like function pointers.
EXPECT_EQ(ToString(Func), ToString(&Func));
}
class OverloadsAddressOp {
public:
OverloadsAddressOp* operator&() { return nullptr; }
const OverloadsAddressOp* operator&() const { return nullptr; }
};
TEST(ToStringTest, NonStringifiable) {
// Non-stringifiable types should be printed using a fallback.
EXPECT_NE(ToString(NotStringifiable()).find("-byte object at 0x"),
std::string::npos);
// Non-stringifiable types which overload operator& should print their real
// address.
EXPECT_NE(ToString(OverloadsAddressOp()),
ToString(static_cast<OverloadsAddressOp*>(nullptr)));
}
} // namespace
} // namespace base