googlemock可以从同一个类的其他方法调用中模拟方法调用吗? [英] Can googlemock mock method calls from within other method calls of the same class?

问题描述

是否可以从同一类的其他方法调用中模拟方法调用?我是C ++的新手(主要是C开发人员)，并且是googlemock和Google Test的新手，所以请原谅我，如果我在其他地方回答了这个问题，但我听不懂答案！下面是一个简单的示例，应该解释我想要做什么.使用下面的示例，我想在测试ReturnInputPlus1时模拟ReturnInput.

Is it possible to mock method calls from within other method calls of the same class? I am new to C++ (primarily a C developer) and very new to googlemock and Google Test so forgive me if this is answered elsewhere and I didn't understand the answer! Below is a simple example that should explain what I want to do. Using the example below, I want to mock ReturnInput, while testing ReturnInputPlus1.

using ::testing::Invoke;
using ::testing::_;
using ::testing::Return;

class MyClass
{
public:
    MyClass() : x(1) {}
    virtual ~MyClass() {}

    int ReturnInput(int x) { return x; }
    int ReturnInputPlus1(int x) { return ReturnInput(x) + 1; }
};

class MockMyClass : public MyClass
{
public:
    MockMyClass()
    {
        ON_CALL(*this, ReturnInput(_)).WillByDefault(Invoke(&real, &MyClass::ReturnInput));
        ON_CALL(*this, ReturnInputPlus1(_)).WillByDefault(Invoke(&real, &MyClass::ReturnInputPlus1));
    }
    virtual ~MockMyClass() {}

    MOCK_METHOD1(ReturnInput, int(int y));
    MOCK_METHOD1(ReturnInputPlus1, int(int));

private:
    MyClass real;
};

TEST(MyClassTest, mockUseClassMethod)
{
    MockMyClass mock;

    EXPECT_CALL(mock, ReturnInput(_))
        .WillOnce(Return(2));
    EXPECT_CALL(mock, ReturnInputPlus1(_))
        .Times(1);

    EXPECT_EQ(3, mock.ReturnInputPlus1(1));
}

运行上述测试时，我希望所有测试都能成功.相反，我得到以下输出:

When I run the above test, I would expect all the tests to succeed. Instead I get the following output:

1>[ RUN      ] MyClassTest.mockUseClassMethod
1>.\MyClassTest.cpp(15): error: Value of: mock.ReturnInputPlus1(1)
1>  Actual: 2
1>Expected: 3
1>.\DllInfoTest.cpp(10): error: Actual function call count doesn't match EXPECT_CALL(mock, ReturnInput(_))...
1>         Expected: to be called once
1>           Actual: never called - unsatisfied and active

推荐答案

默认情况下，您对MockMyClass::ReturnInputPlus1(1)的调用会调用real上的MyClass::ReturnInputPlus1(1)，该调用会调用MyClass::ReturnInput(2).运行ReturnInputPlus1()的对象不是mock，而是mock.real，并且在调用ReturnInput()时会调用该函数的原始版本.您想要做的是创建一个具有ReturnInput()的模拟替代但完全不模拟ReturnInputPlus1()的MockMyClass －您既不想同时拥有该类的模拟版本，又不想拥有一个有时委派给.

Your call to MockMyClass::ReturnInputPlus1(1) calls MyClass::ReturnInputPlus1(1) on real by default, which calls MyClass::ReturnInput(2). The object that ReturnInputPlus1() is running on is not mock, it's mock.real, and when it calls ReturnInput() it calls the original version of the function. What you want to do is create a MockMyClass that has a mock override of ReturnInput() but doesn't mock out ReturnInputPlus1() at all -- you don't want to have both a mock version of your class and a real version that it sometimes delegates to.

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