1 files changed, 78 insertions, 0 deletions
diff --git a/libcxx/test/std/containers/views/span.objectrep/as_bytes.pass.cpp b/libcxx/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
new file mode 100644
index 00000000000..b081b95c373
--- /dev/null
+++ b/libcxx/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
@@ -0,0 +1,78 @@
+// -*- C++ -*-
+//===------------------------------ span ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17 
+
+// <span>
+
+// template <class ElementType, ptrdiff_t Extent>
+//     span<const byte,
+//          Extent == dynamic_extent
+//              ? dynamic_extent
+//              : static_cast<ptrdiff_t>(sizeof(ElementType)) * Extent>
+//     as_bytes(span<ElementType, Extent> s) noexcept;
+
+
+#include <span>
+#include <cassert>
+#include <string>
+
+#include "test_macros.h"
+
+template<typename Span>
+void testRuntimeSpan(Span sp)
+{
+    ASSERT_NOEXCEPT(std::as_bytes(sp));
+
+    auto spBytes = std::as_bytes(sp);
+    using SB = decltype(spBytes);
+    ASSERT_SAME_TYPE(const std::byte, typename SB::element_type);
+
+    if (sp.extent == std::dynamic_extent)
+        assert(spBytes.extent == std::dynamic_extent);
+    else
+        assert(spBytes.extent == static_cast<std::ptrdiff_t>(sizeof(typename Span::element_type)) * sp.extent);
+        
+    assert((void *) spBytes.data() == (void *) sp.data());
+    assert(spBytes.size() == sp.size_bytes());
+}
+
+struct A{};
+int iArr2[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
+
+int main ()
+{
+    testRuntimeSpan(std::span<int>        ());
+    testRuntimeSpan(std::span<long>       ());
+    testRuntimeSpan(std::span<double>     ());
+    testRuntimeSpan(std::span<A>          ());
+    testRuntimeSpan(std::span<std::string>());
+
+    testRuntimeSpan(std::span<int, 0>        ());
+    testRuntimeSpan(std::span<long, 0>       ());
+    testRuntimeSpan(std::span<double, 0>     ());
+    testRuntimeSpan(std::span<A, 0>          ());
+    testRuntimeSpan(std::span<std::string, 0>());
+
+    testRuntimeSpan(std::span<int>(iArr2, 1));
+    testRuntimeSpan(std::span<int>(iArr2, 2));
+    testRuntimeSpan(std::span<int>(iArr2, 3));
+    testRuntimeSpan(std::span<int>(iArr2, 4));
+    testRuntimeSpan(std::span<int>(iArr2, 5));
+
+    testRuntimeSpan(std::span<int, 1>(iArr2 + 5, 1));
+    testRuntimeSpan(std::span<int, 2>(iArr2 + 4, 2));
+    testRuntimeSpan(std::span<int, 3>(iArr2 + 3, 3));
+    testRuntimeSpan(std::span<int, 4>(iArr2 + 2, 4));
+    testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5));
+
+    std::string s;
+    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
+    testRuntimeSpan(std::span<std::string>(&s, 1));
+}