c++ - PrintTo 用于 Google Test 中的指针

Question

如果测试失败，我可以指定如何显示对象的内容。为此，我为该类定义了函数 PrintTo。结果如愿(字符串 MyObject as object):

x.cpp:17: Failure
Value of: foo1
Expected: has foo <MyObject as object>
  Actual: <MyObject as object> (of type Foo)

不幸的是，我找不到如何对指向对象的指针执行相同的操作。我得到的是默认输出，而不是自定义字符串 MyObject as pointer:

x.cpp:22: Failure
Value of: pfoo1
Expected: has foo 0x8058330
  Actual: 0x8058320 (of type Foo*)

作为解决方法，我可以取消引用指针，但我想知道是否有直接的解决方案，即在指针上重载 PrintTo。

#include <gmock/gmock.h>

struct Foo { };

void PrintTo(const Foo& value, ::std::ostream* os) {
  *os << "<MyObject as object>";
}

void PrintTo(const Foo* value, ::std::ostream* os) {
  *os << "<MyObject as pointer>";
}

MATCHER_P(HasFoo, expected, "") { return false; }

TEST(Foo, Object) {
  Foo foo1, foo2;
  ASSERT_THAT(foo1, HasFoo(foo2));
}

TEST(Foo, Pointer) {
  Foo *pfoo1 = new Foo(), *pfoo2 = new Foo();
  ASSERT_THAT(pfoo1, HasFoo(pfoo2));
}

int main(int argc, char** argv) {
  testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

Answer 1

按照@AndyG 和@olaf-dietsche 的建议，应该删除前导的const。这些工作:

Foo* 值

Foo* 常量值

而这些不是:

const Foo* 值

const Foo* 常量值

const Foo*& value