[libcxx] [test] Improve portability of hash tests.

[STL_MSFT]

Summary

Improve portability of hash tests.

These tests were expecting libcxx's identity-hash behavior, which isn't guaranteed by the Standard and isn't provided by MSVC (we currently use FNV-1a for everything). Marking the asserts as libcxx-specific and avoiding unused variable warnings for MSVC makes the tests portable.

[EricWF]

r272744.

test/std/diagnostics/syserr/syserr.hash/error_code.pass.cpp

 
 // template <class T>
 // struct hash
 //     : public unary_function<T, size_t>
 // {
 //     size_t operator()(T val) const;
 // };
 
-// Not very portable
-
 #include <system_error>
 #include <cassert>
 #include <type_traits>
 
+#include "test_macros.h"
+
 void
 test(int i)
 {
     typedef std::error_code T;
     typedef std::hash<T> H;
     static_assert((std::is_same<H::argument_type, T>::value), "" );
     static_assert((std::is_same<H::result_type, std::size_t>::value), "" );
     H h;
     T ec(i, std::system_category());
-    assert(h(ec) == i);
+    const std::size_t result = h(ec);
+    LIBCPP_ASSERT(result == i);
+    ((void)result); // Prevent unused warning
 }
 
 int main()
 {
     test(0);
     test(2);
     test(10);
 }

test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp

 
 // template <class T>
 // struct hash
 //     : public unary_function<T, size_t>
 // {
 //     size_t operator()(T val) const;
 // };
 
-// Not very portable
-
 #include <bitset>
 #include <cassert>
 #include <type_traits>
 
+#include "test_macros.h"
+
 template <std::size_t N>
 void
 test()
 {
     typedef std::bitset<N> T;
     typedef std::hash<T> H;
     static_assert((std::is_same<typename H::argument_type, T>::value), "" );
     static_assert((std::is_same<typename H::result_type, std::size_t>::value), "" );
     H h;
     T bs(static_cast<unsigned long long>(N));
-    assert(h(bs) == N);
+    const std::size_t result = h(bs);
+    LIBCPP_ASSERT(result == N);
+    ((void)result); // Prevent unused warning
 }
 
 int main()
 {
     test<0>();
     test<10>();
     test<100>();
     test<1000>();
 }