1 files changed, 46 insertions, 0 deletions
diff --git a/src/boost/libs/hana/test/concept/struct/keys.cpp b/src/boost/libs/hana/test/concept/struct/keys.cpp
new file mode 100644
index 000000000..c07de9e12
--- /dev/null
+++ b/src/boost/libs/hana/test/concept/struct/keys.cpp
@@ -0,0 +1,46 @@
+// Copyright Louis Dionne 2013-2017
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#include <boost/hana/assert.hpp>
+#include <boost/hana/concept/struct.hpp>
+#include <boost/hana/equal.hpp>
+#include <boost/hana/integral_constant.hpp>
+#include <boost/hana/keys.hpp>
+
+#include "minimal_struct.hpp"
+#include <laws/base.hpp>
+#include <support/seq.hpp>
+namespace hana = boost::hana;
+using hana::test::ct_eq;
+
+
+template <int i = 0>
+struct undefined { };
+
+int main() {
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::keys(obj()),
+        ::seq()
+    ));
+
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::keys(obj(undefined<0>{})),
+        ::seq(hana::int_c<0>)
+    ));
+
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::keys(obj(undefined<0>{}, undefined<1>{})),
+        ::seq(hana::int_c<0>, hana::int_c<1>)
+    ));
+
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::keys(obj(undefined<0>{}, undefined<1>{}, undefined<2>{})),
+        ::seq(hana::int_c<0>, hana::int_c<1>, hana::int_c<2>)
+    ));
+
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::keys(obj(undefined<0>{}, undefined<1>{}, undefined<2>{}, undefined<3>{})),
+        ::seq(hana::int_c<0>, hana::int_c<1>, hana::int_c<2>, hana::int_c<3>)
+    ));
+}