单元测试一个类是不可复制的，以及其他编译时属性

2021-12-09 00:00:00 unit-testing compiler-errors c++

有没有办法测试编译时错误，但实际上不产生错误?例如，如果我创建一个不可复制的类，我想测试以下事实:尝试复制它会产生编译器错误，但我仍然想执行其他运行时测试.

Is there a way to test compile-time errors, but without actually generating the error? For example, if I create a class which is non-copyable, I'd like to test the fact that trying to copy it will generate a compiler error, but I'd still like to execute the other runtime tests.

struct Foo {
    int value_;
    Foo(int value) : value_(value) {}
  private:
    Foo(const Foo&);
    const Foo& operator=(const Foo&);
};

int main()
{
    Foo f(12);
    assert(f.value_ == 12);
    assert(IS_COMPILER_ERROR(Foo copy(f);));
} // Would like this to compile and run fine.

我想这不能像那样简单地完成，但是有没有一种惯用的方法来做到这一点，或者我应该推出自己的解决方案(也许使用脚本编译单独的测试文件并测试结果?)?

I guess this can't be done as simply as that, but is there an idiomatic way to do this, or should I roll my own solution (maybe using scripts compiling separate tests files and testing the results?)?

注意:我采用不可复制只是为了说明我的观点，所以我对有关使用 boost::noncopyable 等的答案不感兴趣.

N.B.: I took non-copyable only to illustrate my point, so I'm not interested in answers about using boost::noncopyable and such.

推荐答案

您可以使用 make 来完成.每个测试都是一个代码片段.这是一个带有 2 个 VC++ 测试的工作示例.(我使用了 2 个批处理文件进行通过测试和失败测试).我在这里使用 GNU make.

You can do it using make. Each test will be a code snippet. Here's a working example with 2 tests for VC++. (I've used 2 batch files for pass test and fail test). I'm using GNU make here.

生成文件:


FAILTEST = .failtest.bat
PASSTEST = .passtest.bat

tests: must_fail_but_passes 
    must_pass_but_fails

must_fail_but_passes:
    @$(FAILTEST) $@.cpp

must_pass_but_fails:
    @$(PASSTEST) $@.cpp

must_pass_but_fails.cpp

must_pass_but_fails.cpp 


struct Foo {
    int value_;
    Foo(void) : value_(0) {}
  private:
    Foo(const Foo&);
    const Foo& operator=(const Foo&);
};

int main(){富 f(12);返回0；}

int main() { Foo f(12); return 0; }

must_fail_but_passes.cpp

must_fail_but_passes.cpp 


struct Foo {
    int value_;
    Foo(int value) : value_(value) {}
  private:
    Foo(const Foo&);
    const Foo& operator=(const Foo&);
};

int main(){富 f(12);返回0；}

int main() { Foo f(12); return 0; }

通过测试.bat


@echo off
cl /nologo %1 >NUL
if %errorlevel% == 0 goto pass
@echo %1 FAILED
:pass

失败测试.bat


@echo off
cl /nologo %1 >NUL
if not %errorlevel% == 0 goto pass
@echo %1 FAILED
:pass

请注意 cl.exe(即 Visual Studio 编译器)需要在您的路径中才能正常工作"

Note that cl.exe (i.e. Visual Studio compiler) need to be in your path for this to "just work"

玩得开心！

附言我怀疑这会让我出名:-)

P.S. I doubt that this would make me famous though :-)

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