CODEWITHSUNDEEP
c++unit-testinginterfacegooglemock
Simon Symon
Simon Symon

Reputation: 45

passing a mock object as an argument of a function

I'm trying to test a class using the google mock framework and can't figure out how to execute my test.

Here is my simplified code:

I have an interface in a .h file:

namespace Mynamespace
{    
    class IMyInterface
    {
    public:
        virtual ~ IMyInterface() {};

        virtual int myFunction() = 0;

    };
}

and my mock class which inherits from the interface:

#include <gmock/gmock.h>
#include <IMyInterface.h>

namespace testing
{
    class MyClassMock : public IMyInterface
    {
    public:
        ~ MyClassMock();
        MyClassMock();

        MOCK_METHOD0(myFunction, int());
    };
}

with the implementation of the mock class:

#include "MyClassMock.h"
namespace testing
{
    MyClassMock:: MyClassMock()
    {
    }

    MyClassMock::~ MyClassMock()
    {
    }
}

my other class takes an object of MyClass as an argument of a function like this:

#include "MyClass.h"

namespace Mynamespace
{
    class AnotherClass
    {
    public:
        AnotherClass();
        ~ AnotherClass();

        void anotherFunction(MyClass&);
    };
}

with the implementation:

#include MyClass.h
#include AnotherClass.h

namespace Mynamespace
{
    AnotherClass:: AnotherClass()
    {
    }
    AnotherClass::~ AnotherClass()
    {
    }
    AnotherClass::anotherFunction(MyClass& obj_myClass)
    {
        //does something...
    }
}

I would then like to test the function of AnotherClass using a mock like this:

#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include "MyClass.h"
#include "MyClassMock.h"
#include "AnotherClass.h"

using namespace testing;
using namespace std;

    TEST(DirectivityParameter, CanInstantiate)
    {
        AnotherClass obj_anotherClass;
        MyClassMock mock_myClass;

        EXPECT_CALL(mock_myClass, myFunction())
            .Times(1)
            .WillOnce(Return(0));

        obj_anotherClass.anotherFunction(&mock_myClass);
    }

This produces the semantic issue: "Non-const lvalue reference to type 'MyClass' cannot bind to a temporary of type 'MyClasssMock *'

I'm confused because I thought the purpose of MyClassMock is to emulate MyClass, but this messages tells me otherwise.

What am I doing wrong? Any help would be very much appreciated!

cheers, Simon

Upvotes: 0

Views: 3088

Answers (1)

Maddy
Maddy

Reputation: 774

You should implement IMyInterface in your class MyClass something like below 

class MyClass :IMyInterface
{
     public:
       virtual int myFunction(); 
}

And you should pass IMyInterface to in your AnotherClass function syntax would be something like below :

class AnotherClass
{
public:
    AnotherClass();
    ~ AnotherClass();

    void anotherFunction(IMyInterface *);
};

then you can test your AnotherClass using your test code

    AnotherClass obj_anotherClass;
    MyClassMock mock_myClass;

    EXPECT_CALL(mock_myClass, myFunction())
        .Times(1)
        .WillOnce(Return(0));

    obj_anotherClass.anotherFunction(&mock_myClass);

Upvotes: 3

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