STL_MSFT created this revision.
STL_MSFT added reviewers: EricWF, mclow.lists.
STL_MSFT added a subscriber: cfe-commits.
[libcxx] [test] Fix non-Standard assumptions when testing sample().
sample() isn't specified with a reproducible algorithm, so expecting
exact output is non-Standard. Mark those tests with LIBCPP_ASSERT.
In test_small_population(), we're guaranteed to get all of the elements,
but not necessarily in their original order. When PopulationCategory is
forward, we're guaranteed stability (and can therefore test equal()).
Otherwise, we can only test is_permutation(). (As it happens, both libcxx
and MSVC's STL provide stability in this scenario for input-only iterators.)
https://reviews.llvm.org/D26816
Files:
test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
Index:
test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
===================================================================
---
test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
+++
test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
@@ -19,9 +19,11 @@
#include <algorithm>
#include <random>
+#include <type_traits>
#include <cassert>
#include "test_iterators.h"
+#include "test_macros.h"
struct ReservoirSampleExpectations {
enum { os = 4 };
@@ -60,19 +62,21 @@
const unsigned os = Expectations::os;
SampleItem oa[os];
const int *oa1 = Expectations::oa1;
+ ((void)oa1); // Prevent unused warning
const int *oa2 = Expectations::oa2;
+ ((void)oa2); // Prevent unused warning
std::minstd_rand g;
SampleIterator end;
end = std::sample(PopulationIterator(ia),
PopulationIterator(ia + is),
SampleIterator(oa), os, g);
assert(end.base() - oa == std::min(os, is));
- assert(std::equal(oa, oa + os, oa1));
+ LIBCPP_ASSERT(std::equal(oa, oa + os, oa1));
end = std::sample(PopulationIterator(ia),
PopulationIterator(ia + is),
SampleIterator(oa), os, std::move(g));
assert(end.base() - oa == std::min(os, is));
- assert(std::equal(oa, oa + os, oa2));
+ LIBCPP_ASSERT(std::equal(oa, oa + os, oa2));
}
template <template<class...> class PopulationIteratorType, class
PopulationItem,
@@ -122,7 +126,12 @@
PopulationIterator(ia + is),
SampleIterator(oa), os, g);
assert(end.base() - oa == std::min(os, is));
- assert(std::equal(oa, end.base(), oa1));
+ typedef typename std::iterator_traits<PopulationIterator>::iterator_category
PopulationCategory;
+ if (std::is_base_of<std::forward_iterator_tag, PopulationCategory>::value) {
+ assert(std::equal(oa, end.base(), oa1));
+ } else {
+ assert(std::is_permutation(oa, end.base(), oa1));
+ }
}
int main() {
Index: test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
===================================================================
--- test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
+++ test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
@@ -19,9 +19,11 @@
#include <algorithm>
#include <random>
+#include <type_traits>
#include <cassert>
#include "test_iterators.h"
+#include "test_macros.h"
struct ReservoirSampleExpectations {
enum { os = 4 };
@@ -60,19 +62,21 @@
const unsigned os = Expectations::os;
SampleItem oa[os];
const int *oa1 = Expectations::oa1;
+ ((void)oa1); // Prevent unused warning
const int *oa2 = Expectations::oa2;
+ ((void)oa2); // Prevent unused warning
std::minstd_rand g;
SampleIterator end;
end = std::sample(PopulationIterator(ia),
PopulationIterator(ia + is),
SampleIterator(oa), os, g);
assert(end.base() - oa == std::min(os, is));
- assert(std::equal(oa, oa + os, oa1));
+ LIBCPP_ASSERT(std::equal(oa, oa + os, oa1));
end = std::sample(PopulationIterator(ia),
PopulationIterator(ia + is),
SampleIterator(oa), os, std::move(g));
assert(end.base() - oa == std::min(os, is));
- assert(std::equal(oa, oa + os, oa2));
+ LIBCPP_ASSERT(std::equal(oa, oa + os, oa2));
}
template <template<class...> class PopulationIteratorType, class PopulationItem,
@@ -122,7 +126,12 @@
PopulationIterator(ia + is),
SampleIterator(oa), os, g);
assert(end.base() - oa == std::min(os, is));
- assert(std::equal(oa, end.base(), oa1));
+ typedef typename std::iterator_traits<PopulationIterator>::iterator_category PopulationCategory;
+ if (std::is_base_of<std::forward_iterator_tag, PopulationCategory>::value) {
+ assert(std::equal(oa, end.base(), oa1));
+ } else {
+ assert(std::is_permutation(oa, end.base(), oa1));
+ }
}
int main() {
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