google test - Checking two different functionalities with single piece of code

Question

What is a correct way to use one implementation of unit test to test two completely different functionalities. In other words, I would like to have two (or more) tests that execute identical code for testing, but differ only in one place - just like in the code below:

TEST(SomeClass, someFunctionality)
{
    // Initialize test (identical)
    // ...

    for (unsigned i = 0; i < 128; i++) {

        // Prepare iteration (identical)
        // ...

        // One test calls here function A() and second test calls function B()
        // and here is the only difference - multiple lines computing arguments
        // for each function call
        // ...

        // Finalize iteration (identical)
        // ...
    }

    // Finalize test (identical)
    // ...
}

Answer 1

You could make a function that both tests share, and pass it a lambda containing the code unique to each test:

template<typename Func>
void testFunctionality(Func func)
{
    // Initialize test
    // ...

    for (unsigned i = 0; i < 128; i++) {

        // Prepare iteration
        // ...

        func();

        // Finalize iteration
        // ...
    }

    // Finalize test
    // ...
}

TEST(SomeClass, someFunctionality)
{
    testFunctionality([]() { A(); });
}
TEST(SomeClass, someOtherFunctionality)
{
    testFunctionality([]() { B(); });
}

You can pass the lambda function whatever arguments you need, e.g. the current iteration i or other local parameters.