From e3f902d6e302c6efad94a1040b6bc81c0780d612 Mon Sep 17 00:00:00 2001
From: King_DuckZ <king_duckz@posteo.net>
Date: Sat, 23 Aug 2025 14:26:11 +0100
Subject: [PATCH] Unit test for SmallObjectAllocator

---
 test/unit/meson.build                     |  1 +
 test/unit/small_object_allocator_test.cpp | 75 +++++++++++++++++++++++
 2 files changed, 76 insertions(+)
 create mode 100644 test/unit/small_object_allocator_test.cpp

diff --git a/test/unit/meson.build b/test/unit/meson.build
index 5086fca..9fa0534 100644
--- a/test/unit/meson.build
+++ b/test/unit/meson.build
@@ -11,6 +11,7 @@ unit_test_prog = executable(meson.project_name(),
   'tiger_test.cpp',
   'infix_iterator.cpp',
   'tree_iterator_test.cpp',
+  'small_object_allocator_test.cpp',
   install: false,
   dependencies: [sprout_dep, catch2_dep],
   include_directories: [public_incl],
diff --git a/test/unit/small_object_allocator_test.cpp b/test/unit/small_object_allocator_test.cpp
new file mode 100644
index 0000000..a7258ab
--- /dev/null
+++ b/test/unit/small_object_allocator_test.cpp
@@ -0,0 +1,75 @@
+/* Copyright 2016-2024 Michele Santullo
+ * This file is part of "duckhandy".
+ *
+ * "duckhandy" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "duckhandy" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "duckhandy".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "catch2/catch_test_macros.hpp"
+#include "duckhandy/small_object_allocator.hpp"
+#include <memory>
+
+namespace {
+static const void* g_alloc_last{nullptr};
+static std::size_t g_alloc_count{0};
+
+template <typename T>
+struct TestAlloc {
+	std::unique_ptr<T> operator()() {
+		auto ret = std::make_unique<T>();
+		g_alloc_last = ret.get();
+		++g_alloc_count;
+		return ret;
+	}
+};
+} //unnamed namespace
+
+TEST_CASE("Check SmallObjectAllocator", "[SmallObjectAllocator][containers][memory][allocators]") {
+	dhandy::SmallObjectAllocator<int, TestAlloc> soa;
+	CHECK(g_alloc_last == nullptr);
+	CHECK(g_alloc_count == 0u);
+
+	int* const int01 = soa.allocate(sizeof(int));
+	const void* old_block = g_alloc_last;
+	REQUIRE(int01 != nullptr);
+	CHECK(g_alloc_last != nullptr);
+	CHECK(g_alloc_count == 1);
+
+	int* const int02 = soa.allocate(sizeof(int));
+	REQUIRE(int02 != nullptr);
+	CHECK(int01 != int02);
+	CHECK(g_alloc_last == old_block);
+	CHECK(g_alloc_count == 1);
+
+	int* prev_int = int02;
+	for (std::size_t z = 2; z < dhandy::SmallObjectAllocator<int, TestAlloc>::objects_per_block; ++z) {
+		int* const new_int = soa.allocate(sizeof(int));
+		REQUIRE(new_int != nullptr);
+		CHECK(new_int != int01);
+		CHECK(new_int != prev_int);
+		prev_int = new_int;
+		CHECK(g_alloc_last == old_block);
+		CHECK(g_alloc_count == 1);
+		CHECK(reinterpret_cast<std::uintptr_t>(new_int) % alignof(int) == 0);
+	}
+
+	int* const int03 = soa.allocate(sizeof(int));
+	REQUIRE(int03 != nullptr);
+	CHECK(int03 != int02);
+	CHECK(int03 != int01);
+	CHECK(g_alloc_last != old_block);
+	old_block = g_alloc_last;
+	CHECK(g_alloc_count == 2);
+
+	soa.deallocate(int02, sizeof(int));
+}