gdb::optional unit tests

I thought I'd add some unit tests to make sure gdb::optional behaved
correctly, and started writing some, but then thought/realized that
libstdc++ already has extensive testing for C++17 std::optional, which
gdb::optional is a subset of, and thought why bother writing something
from scratch.  So I tried copying over a subset of libstdc++'s tests
(that ones that cover the subset supported by gdb::optional), and was
positively surprised that they mostly work OOTB.  This did help shake
out a few bugs from what I was implementing in the previous patch to
gdb::optional.  Still, it's a good chunk of code being copied over, so
if people dislike this copying/duplication, I can drop this patch.

gdb/ChangeLog:
2017-04-18  Pedro Alves  <palves@redhat.com>

	* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
	unittests/optional-selftests.c.
	(SUBDIR_UNITTESTS_OBS): Add optional-selftests.o.
	* unittests/optional-selftests.c: New file.
	* unittests/optional/assignment/1.cc: New file.
	* unittests/optional/assignment/2.cc: New file.
	* unittests/optional/assignment/3.cc: New file.
	* unittests/optional/assignment/4.cc: New file.
	* unittests/optional/assignment/5.cc: New file.
	* unittests/optional/assignment/6.cc: New file.
	* unittests/optional/assignment/7.cc: New file.
	* unittests/optional/cons/copy.cc: New file.
	* unittests/optional/cons/default.cc: New file.
	* unittests/optional/cons/move.cc: New file.
	* unittests/optional/cons/value.cc: New file.
	* unittests/optional/in_place.cc: New file.
	* unittests/optional/observers/1.cc: New file.
	* unittests/optional/observers/2.cc: New file.

1 files changed, 94 insertions, 0 deletions

diff --git a/gdb/unittests/optional-selftests.c b/gdb/unittests/optional-selftests.c
new file mode 100644
index 0000000..76343c6
--- /dev/null
+++ b/gdb/unittests/optional-selftests.c
@@ -0,0 +1,94 @@
+/* Self tests for optional for GDB, the GNU debugger.
+
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "selftest.h"
+#include "common/gdb_optional.h"
+
+/* Used by the included .cc files below.  Included here because the
+   included test files are wrapped in a namespace.  */
+#include <vector>
+#include <string>
+#include <memory>
+
+/* libstdc++'s testsuite uses VERIFY.  */
+#define VERIFY SELF_CHECK
+
+/* Used to disable testing features not supported by
+   gdb::optional.  */
+#define GDB_OPTIONAL
+
+namespace selftests {
+namespace optional {
+
+/* The actual tests live in separate files, which were originally
+   copied over from libstdc++'s testsuite.  To preserve the structure
+   and help with comparison with the original tests, the file names
+   have been preserved, and only minimal modification was done to have
+   them compile against gdb::optional instead of std::optional:
+
+     - std::optional->gdb:optional, etc.
+     - ATTRIBUTE_UNUSED in a few places
+     - wrap each file in a namespace so they can all be compiled as a
+       single unit.
+     - libstdc++'s license and formatting style was preserved.
+*/
+
+#include "optional/assignment/1.cc"
+#include "optional/assignment/2.cc"
+#include "optional/assignment/3.cc"
+#include "optional/assignment/4.cc"
+#include "optional/assignment/5.cc"
+#include "optional/assignment/6.cc"
+#include "optional/assignment/7.cc"
+#include "optional/cons/copy.cc"
+#include "optional/cons/default.cc"
+#include "optional/cons/move.cc"
+#include "optional/cons/value.cc"
+#include "optional/in_place.cc"
+#include "optional/observers/1.cc"
+#include "optional/observers/2.cc"
+
+static void
+run_tests ()
+{
+  assign_1::test ();
+  assign_2::test ();
+  assign_3::test ();
+  assign_4::test ();
+  assign_5::test ();
+  assign_6::test ();
+  assign_7::test ();
+  cons_copy::test ();
+  cons_default::test ();
+  cons_move::test ();
+  cons_value::test ();
+  in_place::test ();
+  observers_1::test ();
+  observers_2::test ();
+}
+
+} /* namespace optional */
+} /* namespace selftests */
+
+void
+_initialize_optional_selftests ()
+{
+  register_self_test (selftests::optional::run_tests);
+}