use std::is_permutation() for unit testing?

[rozick1]

Hi

I'm writing some unit tests where the method tested should return a vector of objects. The method does not guarantee the order of the objects in the returned vector.

As part of the unit tests I have created a vector with the correct objects. I then need to check that the vector returned by the method contains the same objects as the vector with the correct objects.

I'm thinking that std::is_permutation can help here:

vector<thing> correct = {a,b,c,d};
vector<thing> results = test.method();

assert(is_permutation(correct.begin(),correct.end(),results.begin(),results.end()));

I just wondered if this was a good approach?

Thanks

[helios]

That's what the function is for. Alternatively, you could sort both vectors according to the same total order, and it should yield two identical vectors.

[Ganado]

By default, is_permutation uses the == operator between two thing objects to determine equality. So just make sure you have that defined in a sane way (a == b should always be the same as b == a). Other than that, yeah it should work -- if you're having a specific issue, say what it is and we can help.

[dutch]

If your correct vector is already in order, then sorting the result and comparing them is probably more efficient than is_permutation.