如何使用gtest对std :: bind函数进行单元测试? [英] How to unit test the std::bind function using gtest?

问题描述

我正在尝试为项目中的某些cpp文件编写单元测试用例.

I am trying to write unittest cases for some of the cpp files in my project.

这里的场景是: 我有一个cpp文件，其中仅定义了一个公共方法，而后者又调用了私有方法.

The scenario here is: I have a cpp file with only one public method defined and in turn which calls private methods.

在这里，私有方法在公共方法中被称为回调方法.我如何在这里测试私有方法.我将对回调指针进行模拟，但不确定如何调用私有方法.

Here the private methods are called in the public method as a callback method. How do I test the private methods here. I will be doing the mocking for Callback pointer and I am not sure how to call the private method.

请给我一些建议，在这种情况下如何在不更改源代码的情况下调用私有方法.

Please give me some suggestions how to call the private methods in this scenario without changing the source code.

这里是前人:

buttonListenerList <<
 sourceButton->addButtonActionCallback(std::bind(&AudioSource::buttonCallback, this, _1, _2));

这种公共的代码是在public方法中定义的.现在，AudioSource::buttonCallback是私有方法.如何确保通过调用公共方法来调用此私有方法.

This peace of code is defined in the public method. Now the AudioSource::buttonCallback is a private method. How do you make sure to call this private method by calling the public method.

推荐答案

如果，(您在评论中回答是)，可以模拟sourceButton-然后期望调用addButtonActionCallback-并存储传递的std::function<> arg.

If, (you answered yes in comment) sourceButton can be mocked - then expect addButtonActionCallback is called - and store the passed std::function<> arg.

就像下面的示例(用实类型替换...):

Like in the example below (replace ... with real types):

struct TestSuite : public ::testing::Test {
   ...  sourceButtonMock;
   std::unique_ptr<...>  objectUnderTest;
   void SetUp() override;
   std::function<...>  sourceButtonActionCallback;
};
using namespace ::testing;
void TestSuite::SetUp()
{
    EXPECT_CALL(sourceButtonMock, addButtonActionCallback(_))
          .WillOnce(SaveArg<0>(&sourceButtonActionCallback);
    objectUnderTest = std::make_unique<...>(sourceButtonMock);
}

已将此回调存储在sourceButtonActionCallback成员变量中-您可以在任意位置随意调用它:

Having stored this callback in sourceButtonActionCallback member variable - you can call it freely wherever you wish:

TEST_F(TestSuite, shallDo...OnSourceButtonClick)
{
   // prerequisites
   ASSERT_NE(sourceButtonActionCallback, nullptr);

   // Expecteations
   ...

   // action
   sourceButtonActionCallback(...);

   // post-assertions
   ...
}

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