Added debug tests for indexing, pop_back and both forms of erase. Added an improved error message for erasing a single element with end().

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@177929 91177308-0d34-0410-b5e6-96231b3b80d8

test/containers/sequences/vector/vector.modifiers/pop_back.pass.cpp

@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <vector>
+
+// void pop_back();
+
+#if _LIBCPP_DEBUG2 >= 1
+#define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : std::terminate())
+#endif
+
+#include <vector>
+#include <cassert>
+#include "../../../stack_allocator.h"
+
+#if _LIBCPP_DEBUG2 >= 1
+#include <cstdlib>
+#include <exception>
+
+void f1()
+{
+    std::exit(0);
+}
+#endif
+
+int main()
+{
+#if _LIBCPP_DEBUG2 >= 1
+    std::set_terminate(f1);
+#endif
+    {
+        std::vector<int> c;
+        c.push_back(1);
+        assert(c.size() == 1);
+        c.pop_back();
+        assert(c.size() == 0);
+#if _LIBCPP_DEBUG2 >= 1
+        c.pop_back();
+        assert(false);
+#endif        
+    }
+}