Question

在使用valgrind（3.14.0）运行以下虚拟Google Test程序时，我收到一系列警告消息，使我相信该程序的结构可能存在问题。这是我第一次观察到这样的情况，我相信这与FooTest带有std::function实例化参数化的事实有关。

#include <functional>

#include "gtest/gtest.h"

using ::testing::TestWithParam;
using ::testing::Values;


namespace
{

int add(int a, int b)
{
    return a + b;
}

int sub(int a, int b)
{
    return a - b;
}

}

class FooTestHarness
    : public TestWithParam<std::function<int(int, int)>> {};

TEST_P(FooTestHarness, FooTest)
{
  // ...
}

INSTANTIATE_TEST_CASE_P(FooInstantiation, FooTestHarness, Values(add, sub));

以下是（缩短的）valgrind输出的摘录：

==20816== Use of uninitialised value of size 8
==20816==    at 0x4C299BD: _itoa_word (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C2D269: vfprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C55AC5: vsnprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C35503: snprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x13033C: testing::(anonymous namespace)::PrintByteSegmentInObjectTo(unsigned char const*, unsigned long, unsigned long, std::ostream*)
...
==20816== Conditional jump or move depends on uninitialised value(s)
==20816==    at 0x4C299CE: _itoa_word (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C2D269: vfprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C55AC5: vsnprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C35503: snprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x13033C: testing::(anonymous namespace)::PrintByteSegmentInObjectTo(unsigned char const*, unsigned long, unsigned long, std::ostream*)
...
==20816== Conditional jump or move depends on uninitialised value(s)
==20816==    at 0x4C2E100: vfprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C55AC5: vsnprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C35503: snprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x13033C: testing::(anonymous namespace)::PrintByteSegmentInObjectTo(unsigned char const*, unsigned long, unsigned long, std::ostream*)
...
==20816== Conditional jump or move depends on uninitialised value(s)
==20816==    at 0x4C2D3BD: vfprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C55AC5: vsnprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x4C35503: snprintf (in /usr/lib/libc-2.28.so)
==20816==    by 0x13033C: testing::(anonymous namespace)::PrintByteSegmentInObjectTo(unsigned char const*, unsigned long, unsigned long, std::ostream*)
...

GTest的多个版本（包括最新版本）都会发生这种情况。有人可以诊断这是我的错还是GTest和/或valgrind问题？

编辑：如果这是相关的：我在Linux上并使用gcc 8.2.1

Answer 1

我不久前遇到了这个问题，并通过为我的班级实现 operator << 解决了（部分）问题。你可以为 std::function<int(int, int)> 这样做：

#include <ostream>
#include <functional>

std::ostream& operator<<(std::ostream& os, const std::function<int(int, int)>& myFunction) {
  return os << "Do something you wish to represent your function";
}

参考：https://github.com/google/googletest/blob/master/docs/advanced.md#teaching-googletest-how-to-print-your-values

编辑：似乎 GTest 会尝试使用 operator << 打印您的参数（当然这完全有道理）。但是，我仍然不确定这与使用单元化值 valgrind 捕获有何关系。

GTest：使用std :: function参数化测试时的Valgrind警告

1 个答案: