kstd/vector: fix UB in test suite

2 files changed, 79 insertions, 11 deletions

diff --git a/libs/kstd/kstd/test_support/test_types.hpp b/libs/kstd/kstd/test_support/test_types.hpp
index 8231fd3b..baf5e853 100644
--- a/libs/kstd/kstd/test_support/test_types.hpp
+++ b/libs/kstd/kstd/test_support/test_types.hpp
@@ -13,6 +13,28 @@ namespace kstd::tests
   //! This type is designed to test move and copy semantics of standard library containers implemented in kstd.
   struct special_member_tracker
   {
+    struct counters
+    {
+      //! A counter to track how many times an instance of this type was default constructed.
+      std::size_t default_constructed{0};
+      //! A counter to track how many times an instance of this type was copy constructed.
+      std::size_t copy_constructed{0};
+      //! A counter to track how many times an instance of this type was move constructed.
+      std::size_t move_constructed{0};
+      //! A counter to track how many times an instance of this type was value constructed.
+      std::size_t value_constructed{0};
+      //! A counter to track how many times an instance of this type was copy assigned.
+      std::size_t copy_assigned{0};
+      //! A counter to track how many times an instance of this type was move assigned.
+      std::size_t move_assigned{0};
+      //! A counter to track how many times an instance of this type was destroyed.
+      std::size_t destroyed{0};
+      //! A counter to track how many times an instance of this type was copied from another instance.
+      std::size_t copied_from{0};
+      //! A counter to track how many times an instance of this type was moved from another instance.
+      std::size_t moved_from{0};
+    } * external = nullptr;
+
     //! A value indicating that the object was moved from.
     constexpr auto static moved_from_v = -1;
 
@@ -47,7 +69,15 @@ namespace kstd::tests
       {
         value = other.value;
         ++copy_assigned_count;
+        if (external)
+        {
+          ++external->copy_assigned;
+        }
         ++other.copied_from_count;
+        if (other.external)
+        {
+          ++other.external->copied_from;
+        }
       }
       return *this;
     }
@@ -61,8 +91,16 @@ namespace kstd::tests
       {
         value = other.value;
         ++move_assigned_count;
+        if (external)
+        {
+          ++external->move_assigned;
+        }
         other.value = moved_from_v;
         ++other.moved_from_count;
+        if (other.external)
+        {
+          ++other.external->moved_from;
+        }
       }
       return *this;
     }
@@ -70,6 +108,24 @@ namespace kstd::tests
     ~special_member_tracker()
     {
       ++destroyed_count;
+      if (external)
+      {
+        ++external->destroyed;
+      }
+    }
+
+    auto set_external_counters(counters & counters) noexcept
+    {
+      external = &counters;
+      external->default_constructed = default_constructed_count;
+      external->copy_constructed = copy_constructed_count;
+      external->move_constructed = move_constructed_count;
+      external->value_constructed = value_constructed_count;
+      external->copy_assigned = copy_assigned_count;
+      external->move_assigned = move_assigned_count;
+      external->destroyed = destroyed_count;
+      external->copied_from = copied_from_count;
+      external->moved_from = moved_from_count;
     }
 
     auto reset_counts() -> void
diff --git a/libs/kstd/kstd/vector.tests.cpp b/libs/kstd/kstd/vector.tests.cpp
index 24598bf9..ed0695fb 100644
--- a/libs/kstd/kstd/vector.tests.cpp
+++ b/libs/kstd/kstd/vector.tests.cpp
@@ -1628,6 +1628,9 @@ SCENARIO("Vector modifier move semantics", "[vector]")
         elem.reset_counts();
       }
 
+      auto counters = kstd::tests::special_member_tracker::counters{};
+      v[2].set_external_counters(counters);
+
       auto it = v.erase(v.cbegin() + 1);
 
       THEN("the subsequent elements are move-assigned leftwards")
@@ -1642,8 +1645,8 @@ SCENARIO("Vector modifier move semantics", "[vector]")
         REQUIRE(v[1].move_assigned_count == 1);
         REQUIRE(v[1].copy_assigned_count == 0);
 
-        REQUIRE(v.data()[2].destroyed_count == 1);
-        REQUIRE(v.data()[2].moved_from_count == 1);
+        REQUIRE(counters.destroyed == 1);
+        REQUIRE(counters.moved_from == 1);
 
         REQUIRE(it == v.begin() + 1);
       }
@@ -1656,6 +1659,9 @@ SCENARIO("Vector modifier move semantics", "[vector]")
         elem.reset_counts();
       }
 
+      auto counters = kstd::tests::special_member_tracker::counters{};
+      v[2].set_external_counters(counters);
+
       auto it = v.erase(v.cend() - 1);
 
       THEN("no elements are moved, just the last element destroyed")
@@ -1674,9 +1680,9 @@ SCENARIO("Vector modifier move semantics", "[vector]")
         REQUIRE(v[1].move_assigned_count == 0);
         REQUIRE(v[1].copy_assigned_count == 0);
 
-        REQUIRE(v.data()[2].destroyed_count == 1);
-        REQUIRE(v.data()[2].moved_from_count == 0);
-        REQUIRE(v.data()[2].copied_from_count == 0);
+        REQUIRE(counters.destroyed == 1);
+        REQUIRE(counters.moved_from == 0);
+        REQUIRE(counters.copied_from == 0);
 
         REQUIRE(it == v.end());
       }
@@ -1692,6 +1698,12 @@ SCENARIO("Vector modifier move semantics", "[vector]")
         elem.reset_counts();
       }
 
+      auto counters3 = kstd::tests::special_member_tracker::counters{};
+      v[3].set_external_counters(counters3);
+
+      auto counters4 = kstd::tests::special_member_tracker::counters{};
+      v[4].set_external_counters(counters4);
+
       auto it = v.erase(v.cbegin() + 1, v.cbegin() + 3);
 
       THEN("the specified elements are destroyed and subsequent elements are move-assigned leftwards")
@@ -1716,13 +1728,13 @@ SCENARIO("Vector modifier move semantics", "[vector]")
         REQUIRE(v[2].move_assigned_count == 1);
         REQUIRE(v[2].copy_assigned_count == 0);
 
-        REQUIRE(v.data()[3].destroyed_count == 1);
-        REQUIRE(v.data()[3].moved_from_count == 1);
-        REQUIRE(v.data()[3].copied_from_count == 0);
+        REQUIRE(counters3.destroyed == 1);
+        REQUIRE(counters3.moved_from == 1);
+        REQUIRE(counters3.copied_from == 0);
 
-        REQUIRE(v.data()[4].destroyed_count == 1);
-        REQUIRE(v.data()[4].moved_from_count == 1);
-        REQUIRE(v.data()[4].copied_from_count == 0);
+        REQUIRE(counters4.destroyed == 1);
+        REQUIRE(counters4.moved_from == 1);
+        REQUIRE(counters4.copied_from == 0);
 
         REQUIRE(it == v.begin() + 1);
       }