Implement tests for NULL iterators for <array> re: N3644

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@187809 91177308-0d34-0410-b5e6-96231b3b80d8

test/containers/sequences/array/iterators.pass.cpp

@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+
+// iterator, const_iterator
+
+#include <array>
+#include <iterator>
+#include <cassert>
+
+int main()
+{
+    {
+    typedef std::array<int, 5> C;
+    C c;
+    C::iterator i;
+    i = c.begin();
+    C::const_iterator j;
+    j = c.cbegin();
+    assert(i == j);
+    }
+    {
+    typedef std::array<int, 0> C;
+    C c;
+    C::iterator i;
+    i = c.begin();
+    C::const_iterator j;
+    j = c.cbegin();
+    assert(i == j);
+    }
+
+#if _LIBCPP_STD_VER > 11
+    { // N3664 testing
+        {
+        typedef std::array<int, 5> C;
+        C::iterator ii1{}, ii2{};
+        C::iterator ii4 = ii1;
+        C::const_iterator cii{};
+        assert ( ii1 == ii2 );
+        assert ( ii1 == ii4 );
+        assert ( ii1 == cii );
+
+        assert ( !(ii1 != ii2 ));
+        assert ( !(ii1 != cii ));
+
+//         C c;
+//         assert ( ii1 != c.cbegin());
+//         assert ( cii != c.begin());
+//         assert ( cii != c.cend());
+//         assert ( ii1 != c.end());
+        }
+        {
+        typedef std::array<int, 0> C;
+        C::iterator ii1{}, ii2{};
+        C::iterator ii4 = ii1;
+        C::const_iterator cii{};
+        assert ( ii1 == ii2 );
+        assert ( ii1 == ii4 );
+        assert ( ii1 == cii );
+
+        assert ( !(ii1 != ii2 ));
+        assert ( !(ii1 != cii ));
+
+//         C c;
+//         assert ( ii1 != c.cbegin());
+//         assert ( cii != c.begin());
+//         assert ( cii != c.cend());
+//         assert ( ii1 != c.end());
+        }
+    }
+#endif
+}