xo-gc stack: fix mutation setup + xo-reader2 utest

utest/dp.test.cpp

@@ -0,0 +1,100 @@
+/** @file dp.test.cpp
+ *
+ *  @author Roland Conybeare, May 2026
+ **/
+
+#include "dp.hpp"
+#include <xo/alloc2/Allocator.hpp>
+#include <xo/alloc2/Arena.hpp>
+#include <catch2/catch.hpp>
+
+namespace xo {
+    using xo::mm::AAllocator;
+    using xo::mm::DArena;
+    using xo::mm::ArenaConfig;
+
+    namespace {
+        class Foo {
+        public:
+            explicit Foo(uint32_t * p_counter) : p_counter_{p_counter} {}
+
+            static constexpr bool is_gc_eligible() { return false; }
+
+            ~Foo() {
+                ++(*p_counter_);
+            }
+
+        private:
+            uint32_t * p_counter_ = nullptr;
+        };
+    }
+
+    namespace ut {
+
+        TEST_CASE("dp-1", "[dp]")
+        {
+            //ArenaConfig cfg { .name_ = "testarena", .size_ = 1024 };
+            //DArena arena = DArena::map(cfg);
+            //auto mm = obj<AAllocator,DArena>(&arena);
+
+            uint32_t counter = 0;
+            Foo foo(&counter);
+
+            REQUIRE(counter == 0);
+            {
+                dp<Foo> foo_dp(&foo);
+
+                REQUIRE(foo_dp);
+                REQUIRE(foo_dp.data());
+                REQUIRE(foo_dp.is_gc_eligible() == false);
+
+                // foo_dp dtor runs here, increments counter
+            }
+            REQUIRE(counter == 1);
+        }
+
+        TEST_CASE("dp-2", "[dp]")
+        {
+            uint32_t counter = 0;
+            Foo foo(&counter);
+
+            REQUIRE(counter == 0);
+            {
+                dp<Foo> foo_dp(&foo);
+
+                REQUIRE(foo_dp);
+                REQUIRE(foo_dp.data() == &foo);
+
+                foo_dp.release();
+
+                REQUIRE(!foo_dp);
+                REQUIRE(!foo_dp.data());
+
+                // foo_dp dtor runs here, increments counter
+            }
+            REQUIRE(counter == 0);
+        }
+
+        TEST_CASE("dp-DArena", "[dp][DArena]")
+        {
+            ArenaConfig cfg { .name_ = "testarena", .size_ = 1024 };
+            DArena arena = DArena::map(cfg);
+            //auto mm = obj<AAllocator,DArena>(&arena);
+
+            REQUIRE(arena.reserved() > 0);
+            REQUIRE(arena.is_mapped());
+            {
+                dp<DArena> arena_dp(&arena);
+
+                REQUIRE(arena_dp);
+                REQUIRE(arena_dp.data() == &arena);
+            }
+
+            REQUIRE(arena.reserved() == 0);
+            REQUIRE(!arena.is_mapped());
+        }
+
+    } /*namespace ut*/
+} /*namespace xo*/
+
+/* end dp.test.cpp */