unique_ptr : calling make_unique twice one after the other

Question

1 std::unique_ptr< Test[] > upt(std::make_unique< Test[] >(2));

//No leak here, as it does reset, which will deallocate.

3 upt = (std::make_unique< Test[] >(1));

In the above snippet, on call to line 3, twice destructors of Test gets called, and allocates memory for array of size 1,

So, who call the reset? Is it make_unique does it? Also, can I get detail implementation of make_unique and make_shared .