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diff --git a/src/boost/libs/hana/test/_include/auto/unfolds.hpp b/src/boost/libs/hana/test/_include/auto/unfolds.hpp
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--- /dev/null
+++ b/src/boost/libs/hana/test/_include/auto/unfolds.hpp
@@ -0,0 +1,170 @@
+// 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)
+
+#ifndef BOOST_HANA_TEST_AUTO_UNFOLDS_HPP
+#define BOOST_HANA_TEST_AUTO_UNFOLDS_HPP
+
+#include <boost/hana/assert.hpp>
+#include <boost/hana/equal.hpp>
+#include <boost/hana/fold_left.hpp>
+#include <boost/hana/fold_right.hpp>
+#include <boost/hana/if.hpp>
+#include <boost/hana/integral_constant.hpp>
+#include <boost/hana/optional.hpp>
+#include <boost/hana/plus.hpp>
+#include <boost/hana/unfold_left.hpp>
+#include <boost/hana/unfold_right.hpp>
+
+#include <laws/base.hpp>
+#include <support/minimal_product.hpp>
+#include "test_case.hpp"
+
+
+TestCase test_unfold_left{[]{
+    namespace hana = boost::hana;
+
+    hana::test::_injection<0> f{};
+    auto stop_at = [=](auto stop) {
+        return [=](auto x) {
+            return hana::if_(hana::equal(stop, x),
+                hana::nothing,
+                hana::just(::minimal_product(x + hana::int_c<1>, f(x)))
+            );
+        };
+    };
+
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_left<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<0>)),
+        MAKE_TUPLE()
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_left<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<1>)),
+        MAKE_TUPLE(f(hana::int_c<0>))
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_left<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<2>)),
+        MAKE_TUPLE(f(hana::int_c<1>), f(hana::int_c<0>))
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_left<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<3>)),
+        MAKE_TUPLE(f(hana::int_c<2>), f(hana::int_c<1>), f(hana::int_c<0>))
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_left<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<4>)),
+        MAKE_TUPLE(f(hana::int_c<3>), f(hana::int_c<2>), f(hana::int_c<1>), f(hana::int_c<0>))
+    ));
+}};
+
+
+TestCase test_unfold_right{[]{
+    namespace hana = boost::hana;
+
+    hana::test::_injection<0> f{};
+    auto stop_at = [=](auto stop) {
+        return [=](auto x) {
+            return hana::if_(hana::equal(stop, x),
+                hana::nothing,
+                hana::just(::minimal_product(f(x), x + hana::int_c<1>))
+            );
+        };
+    };
+
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_right<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<0>)),
+        MAKE_TUPLE()
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_right<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<1>)),
+        MAKE_TUPLE(f(hana::int_c<0>))
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_right<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<2>)),
+        MAKE_TUPLE(f(hana::int_c<0>), f(hana::int_c<1>))
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_right<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<3>)),
+        MAKE_TUPLE(f(hana::int_c<0>), f(hana::int_c<1>), f(hana::int_c<2>))
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        hana::unfold_right<TUPLE_TAG>(hana::int_c<0>, stop_at(hana::int_c<4>)),
+        MAKE_TUPLE(f(hana::int_c<0>), f(hana::int_c<1>), f(hana::int_c<2>), f(hana::int_c<3>))
+    ));
+}};
+
+// Make sure unfolds can be reversed under certain conditions.
+TestCase test_unfold_undo{[]{
+    namespace hana = boost::hana;
+    using hana::test::ct_eq;
+
+    auto z = ct_eq<999>{};
+    auto f = ::minimal_product;
+    auto g = [=](auto k) {
+        return hana::if_(hana::equal(k, z),
+            hana::nothing,
+            hana::just(k)
+        );
+    };
+
+    // Make sure the special conditions are met
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        g(z),
+        hana::nothing
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        g(f(ct_eq<0>{}, z)),
+        hana::just(::minimal_product(ct_eq<0>{}, z))
+    ));
+    BOOST_HANA_CONSTANT_CHECK(hana::equal(
+        g(f(z, ct_eq<0>{})),
+        hana::just(::minimal_product(z, ct_eq<0>{}))
+    ));
+
+    // Make sure the reversing works
+    {
+        auto xs = MAKE_TUPLE();
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_left<TUPLE_TAG>(hana::fold_left(xs, z, f), g),
+            xs
+        ));
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_right<TUPLE_TAG>(hana::fold_right(xs, z, f), g),
+            xs
+        ));
+    }
+    {
+        auto xs = MAKE_TUPLE(ct_eq<0>{});
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_left<TUPLE_TAG>(hana::fold_left(xs, z, f), g),
+            xs
+        ));
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_right<TUPLE_TAG>(hana::fold_right(xs, z, f), g),
+            xs
+        ));
+    }
+    {
+        auto xs = MAKE_TUPLE(ct_eq<0>{}, ct_eq<1>{});
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_left<TUPLE_TAG>(hana::fold_left(xs, z, f), g),
+            xs
+        ));
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_right<TUPLE_TAG>(hana::fold_right(xs, z, f), g),
+            xs
+        ));
+    }
+    {
+        auto xs = MAKE_TUPLE(ct_eq<0>{}, ct_eq<1>{}, ct_eq<2>{});
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_left<TUPLE_TAG>(hana::fold_left(xs, z, f), g),
+            xs
+        ));
+        BOOST_HANA_CONSTANT_CHECK(hana::equal(
+            hana::unfold_right<TUPLE_TAG>(hana::fold_right(xs, z, f), g),
+            xs
+        ));
+    }
+}};
+
+#endif // !BOOST_HANA_TEST_AUTO_UNFOLDS_HPP