string_view: add string_view forward iterator API libcxx tests

- taken from: llvm-mirror/libcxx@78d6a77

Author: KFilipek

tests/external/libcxx/string.view/string.view.iterators/begin.pass.cpp

@@ -0,0 +1,95 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <string_view>
+
+// constexpr const_iterator begin() const;
+
+#include <string_view>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class S>
+void
+test(S s)
+{
+    const S& cs = s;
+    typename S::iterator b = s.begin();
+    typename S::const_iterator cb1 = cs.begin();
+    typename S::const_iterator cb2 = s.cbegin();
+    if (!s.empty())
+    {
+        assert(   *b ==  s[0]);
+        assert(  &*b == &s[0]);
+        assert( *cb1 ==  s[0]);
+        assert(&*cb1 == &s[0]);
+        assert( *cb2 ==  s[0]);
+        assert(&*cb2 == &s[0]);
+
+    }
+    assert(  b == cb1);
+    assert(  b == cb2);
+    assert(cb1 == cb2);
+}
+
+
+int main(int, char**)
+{
+    typedef std::string_view    string_view;
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    typedef std::u8string_view  u8string_view;
+#endif
+    typedef std::u16string_view u16string_view;
+    typedef std::u32string_view u32string_view;
+    typedef std::wstring_view   wstring_view;
+
+    test(string_view   ());
+    test(u16string_view());
+    test(u32string_view());
+    test(wstring_view  ());
+    test(string_view   ( "123"));
+    test(wstring_view  (L"123"));
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    test(u8string_view{u8"123"});
+#endif
+#if TEST_STD_VER >= 11
+    test(u16string_view{u"123"});
+    test(u32string_view{U"123"});
+#endif
+
+#if TEST_STD_VER > 11
+    {
+    constexpr string_view       sv { "123", 3 };
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    constexpr u8string_view u8sv  {u8"123", 3 };
+#endif
+    constexpr u16string_view u16sv {u"123", 3 };
+    constexpr u32string_view u32sv {U"123", 3 };
+    constexpr wstring_view     wsv {L"123", 3 };
+
+    static_assert (    *sv.begin() ==    sv[0], "" );
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    static_assert (  *u8sv.begin() ==  u8sv[0], "" );
+#endif
+    static_assert ( *u16sv.begin() == u16sv[0], "" );
+    static_assert ( *u32sv.begin() == u32sv[0], "" );
+    static_assert (   *wsv.begin() ==   wsv[0], "" );
+
+    static_assert (    *sv.cbegin() ==    sv[0], "" );
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    static_assert (  *u8sv.cbegin() ==  u8sv[0], "" );
+#endif
+    static_assert ( *u16sv.cbegin() == u16sv[0], "" );
+    static_assert ( *u32sv.cbegin() == u32sv[0], "" );
+    static_assert (   *wsv.cbegin() ==   wsv[0], "" );
+    }
+#endif
+
+  return 0;
+}

tests/external/libcxx/string.view/string.view.iterators/end.pass.cpp

@@ -0,0 +1,104 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <string_view>
+
+// constexpr const_iterator end() const;
+
+#include <string_view>
+#include <cassert>
+#include <cstddef>
+
+#include "test_macros.h"
+
+template <class S>
+void
+test(S s)
+{
+    const S& cs = s;
+    typename S::iterator e = s.end();
+    typename S::const_iterator ce1 = cs.end();
+    typename S::const_iterator ce2 = s.cend();
+
+    if (s.empty())
+    {
+        assert(  e ==  s.begin());
+        assert(ce1 == cs.begin());
+        assert(ce2 ==  s.begin());
+    }
+    else
+    {
+        assert(  e !=  s.begin());
+        assert(ce1 != cs.begin());
+        assert(ce2 !=  s.begin());
+    }
+
+    assert(static_cast<std::size_t>(  e -  s.begin()) == s.size());
+    assert(static_cast<std::size_t>(ce1 - cs.begin()) == cs.size());
+    assert(static_cast<std::size_t>(ce2 - s.cbegin()) == s.size());
+
+    assert(  e == ce1);
+    assert(  e == ce2);
+    assert(ce1 == ce2);
+}
+
+
+int main(int, char**)
+{
+    typedef std::string_view    string_view;
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    typedef std::u8string_view  u8string_view;
+#endif
+    typedef std::u16string_view u16string_view;
+    typedef std::u32string_view u32string_view;
+    typedef std::wstring_view   wstring_view;
+
+    test(string_view   ());
+    test(u16string_view());
+    test(u32string_view());
+    test(wstring_view  ());
+    test(string_view   ( "123"));
+    test(wstring_view  (L"123"));
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    test(u8string_view{u8"123"});
+#endif
+#if TEST_STD_VER >= 11
+    test(u16string_view{u"123"});
+    test(u32string_view{U"123"});
+#endif
+
+#if TEST_STD_VER > 11
+    {
+    constexpr string_view       sv { "123", 3 };
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    constexpr u8string_view u8sv  {u8"123", 3 };
+#endif
+    constexpr u16string_view u16sv {u"123", 3 };
+    constexpr u32string_view u32sv {U"123", 3 };
+    constexpr wstring_view     wsv {L"123", 3 };
+
+    static_assert (    sv.begin() !=    sv.end(), "" );
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    static_assert (  u8sv.begin() !=  u8sv.end(), "" );
+#endif
+    static_assert ( u16sv.begin() != u16sv.end(), "" );
+    static_assert ( u32sv.begin() != u32sv.end(), "" );
+    static_assert (   wsv.begin() !=   wsv.end(), "" );
+
+    static_assert (    sv.begin() !=    sv.cend(), "" );
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+    static_assert (  u8sv.begin() !=  u8sv.cend(), "" );
+#endif
+    static_assert ( u16sv.begin() != u16sv.cend(), "" );
+    static_assert ( u32sv.begin() != u32sv.cend(), "" );
+    static_assert (   wsv.begin() !=   wsv.cend(), "" );
+    }
+#endif
+
+  return 0;
+}