how to cast const vector to non-const

Question

I am doing a gtest. The function I would like to test takes two parameters.

int functionA(const ObjectA& obja, const stl::vector<ObjectB>& objb)

In my gtest, I would like to mock some test cases.

For obja, what I did is:

ObjectA* obja = new ObjectA();
obja->type() = someValue; //setter function
obja->value() = someValue; // setter too

and then pass *(const_cast<ObjectA*>(obja)) as the parameter.

But for the vector, I am not sure what const defines. I tried:

stl::vector<ObjectB*>*  input;
ObjectB objb = new ObjectB();
objb->type() = someValue // setter
objb->id() = someValue//setter
input.push_back(objb);

then pass *(const_cast<ObjectB*>(input)) as the parameter.

But I get an error message saying "no matching function".

Could anyone tell me how I can mock input and pass it in gtest?

For your convenience, the code in gtest is (assume class name is A):

ObjectA* obja = new ObjectA();
obja->type() = someValue; //setter function
obja->value() = someValue; // setter too

stl::vector<ObjectB*>*  input;
ObjectB objb = new ObjectB();
objb->type() = someValue // setter
objb->id() = someValue//setter
input.push_back(objb);

A* instanceA = A::getInstance();
EXPECT_EQ(-2, instanceA->functionA(*(const_cast<ObjectA*>(obja)),*(const_cast<ObjectB*>(input)))) ;

I also tried not using const_cast and pointers, I tried:

const ObjectA a;
a.type() = somevalue;
a.value() = somevalue;

const stl::vector<ObjectB> input;
ObjectB objb;
objb.type() = some;
input.push_back(objb);

and just pass input and a as parameters in test.

but I get an error saying "lvalue required as left operand of assignment" on a.type() = somevalue;

I think it is because there are two type() in class ObjectA, one is a setter without const, one is a getter with const. If I declare a as const, it believes type() is the getter rather than the setter, so it cannot be a left-side value. That's why I want to use const_cast.

Answer 1

Forget about const, that's not the issue, The problem is the unnecessary and sometimes incorrect use of pointers.

Look at the declaration of the function you are testing.

int functionA(const ObjectA& obja, const stl::vector<ObjectB>& objb)

No pointers there. Now look at the declaration of the vector you are trying to pass to the function.

stl::vector<ObjectB*>*  input;

That's (a pointer to) a vector of pointers, that's why the code doesn't work. The test function vector is not a vector of pointers. Here's how to write the code without any pointers.

ObjectA obja;
obja.type() = someValue; //setter function
obja.value() = someValue; // setter too

stl::vector<ObjectB> input;
ObjectB objb;
objb.type() = someValue // setter
objb.id() = someValue//setter
input.push_back(objb);

A* instanceA = A::getInstance();
EXPECT_EQ(-2, instanceA->functionA(obja, input));

Much easier.