Automatic generation of mock classes for gmock

Question

I am using gmock for unit testing C++ code. I am not using the gtest framework. I am using visual studio 2008's built-in testing framework.

Now my problem is that I have to manually write mock classes for a real class to unit test. For example if I have A class with 5 functions then I have to write MockAClass with 5 functions. Is there any way that these classes are automatically generated.

class AClass
{
public:
    virtual int AFunction()
    {
        return 5;
    }
    virtual int AFunctionWithArguments(int x)
    {
        return x;
    }



class MockAClass : public AClass
{
public:
    MOCK_METHOD0(AFucntion, int());
    MOCK_METHOD1(AFunctionWithArgument, int(int x));
};

score 20 · Accepted Answer · edited Apr 14 '17 at 10:22

There is a tool bundled with the google mock project that will help you do this. However I think the tool requires python to be installed, and I don't know how well it works in a windows environment. I've also found that the generated files sometimes need a little tweak to work perfectly.

Here's the info from the docs:

Tip: If even this is too much work for you, you'll find the gmock_gen.py tool in Google Mock's scripts/generator/ directory (courtesy of the cppclean project) useful. This command-line tool requires that you have Python 2.4 installed. You give it a C++ file and the name of an abstract class defined in it, and it will print the definition of the mock class for you. Due to the complexity of the C++ language, this script may not always work, but it can be quite handy when it does. For more details, read the user documentation.

Here is new localization of this script.

This definitely works on Windows. I'm at Python 2.7 and it's fine. Usual caveats apply for hand tweaks... — rholmes, Feb 20 '14 at 23:12

Dror Helper · Answer 2 · 2012-02-13T08:09:21.420

3

Disclaimer: I used to work at Typemock

Have you considered using another tool?
Typemock has a tool called Isolator++ that do not need you to write "mocking classes".

TEST_F(IsolatorTests, SomeTest) 
{
      AClass* fakeclass = FAKE(AClass);
      WHEN_CALLED(fakeclass->AFunction()).Return(10);

      ASSERT_EQ(10, fakeclass.AFunction()); 
}

You can learn more about it at this about page

edited Feb 13 '12 at 08:09

answered Feb 13 '12 at 07:22

Dror Helper

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i have read about isolator++. but that is not free. you have to get license for that. – fhnaseer Feb 13 '12 at 07:27
3

@DrorHelper Probably worth a disclaimer that you used to work for Typemock. (Not that that makes it a bad product etc, but its good to disclose such potential sources of bias). – Michael Anderson Feb 13 '12 at 07:48
1

Moq (http://code.google.com/p/moq/) is a free library for c# unit testing. isolator++ is same for c++ but they are asking money. i want a free library. dont have money to spent on that. i buy isolator++ for 600 dollars while the application i am making is of 200 dollar. doesnt make any sense to use isolator++. – fhnaseer Feb 13 '12 at 07:52
@Michael Anderson I would add the disclaimer although I don't see the relevnace - since I no longer work there – Dror Helper Feb 13 '12 at 08:08
@fhnaseer the sad truth is that usually it's a matter of trade-off either spend your money or your time (equals money). I wish I knew of a free (preferably open source) tool that can help you but I'm not aware of one. Another option is to use a manager C++ wrapper and use .NET (free) mocking framework but it seems like a lot of work. – Dror Helper Feb 13 '12 at 08:10
somebody told me that there are scripts which can do this, any idea about that, – fhnaseer Feb 13 '12 at 09:18

Automatic generation of mock classes for gmock

2 Answers2