gribozavr added inline comments.
================
Comment at:
test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.pass.cpp:35
@@ -30,1 +34,3 @@
}
+
+template <class Iter>
----------------
mclow.lists wrote:
> This is not how I would rewrite this test.
> I would write a routine that took two "iterators", and called
> `random_shuffle`, and then checked for the desired results.
>
> Then call it with pointers. and RA iters, etc.
> for example:
>
> template <Class Iter>
> void test(Iter first, Iter last, Iter resFirst, Iter resLast);
>
> test(nullptr, nullptr, nullptr, nullptr);
> int source[] = {1, 2, 3, 4};
> int res [] = {1, 2, 3, 4};
> const unsigned size = sizeof(source)/sizeof(source[0]);
>
> test(source, source + size, res, res+size);
> test(random_access_iterator<int*>(source) .... );
>
>
I actually thought about this, and it is hard to rewrite it like that for two
reasons. First, `random_shuffle` mutates the elements, so one needs to restore
the original sequence between calls to `test()` (otherwise it is not obvious
that it was mutated). Second, this overload of `random_shuffle` takes
randomness from global state, so one can't just specify one expected result in
the test. That's why I first check for the initial shuffle exactly, and then
only check that the output is a permutation of input.
Repository:
rL LLVM
http://reviews.llvm.org/D14686
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