util/saveload: implement default saveload for std::optional

1 files changed, 21 insertions, 0 deletions

diff --git a/util/ysaveload_ut.cpp b/util/ysaveload_ut.cpp
index 7656f8e941..23152ed929 100644
--- a/util/ysaveload_ut.cpp
+++ b/util/ysaveload_ut.cpp
@@ -27,6 +27,7 @@ class TSaveLoadTest: public TTestBase {
     UNIT_TEST(TestList)
     UNIT_TEST(TestTuple)
     UNIT_TEST(TestVariant)
+    UNIT_TEST(TestOptional)
     UNIT_TEST(TestInheritNonVirtualClass)
     UNIT_TEST(TestInheritVirtualClass)
     UNIT_TEST_SUITE_END();
@@ -429,6 +430,26 @@ private:
         UNIT_ASSERT_EXCEPTION(::Load(&s, v2), TLoadEOF);
     }
 
+    template <class T>
+    void TestOptionalImpl(const std::optional<T>& v) {
+        std::optional<T> loaded;
+        TBufferStream s;
+        ::Save(&s, v);
+        ::Load(&s, loaded);
+
+        UNIT_ASSERT_VALUES_EQUAL(v.has_value(), loaded.has_value());
+        if (v.has_value()) {
+            UNIT_ASSERT_VALUES_EQUAL(*v, *loaded);
+        }
+    }
+
+    void TestOptional() {
+        TestOptionalImpl(std::optional<ui64>(42ull));
+        TestOptionalImpl(std::optional<bool>(true));
+        TestOptionalImpl(std::optional<TString>("abacaba"));
+        TestOptionalImpl(std::optional<ui64>(std::nullopt));
+    }
+
     //  tests serialization of class with three public string members
     template <class TDerived, class TInterface = TDerived>
     void TestInheritClassImpl() {