优化了平衡，尤其对于向后倾倒的几种极限情况进行优化

Shibo-main-TOMMY/lib/ArduinoJson/extras/tests/MemoryPool/allocVariant.cpp

@@ -0,0 +1,50 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2023, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson/Memory/MemoryPool.hpp>
+#include <catch.hpp>
+
+using namespace ArduinoJson::detail;
+
+TEST_CASE("MemoryPool::allocVariant()") {
+  char buffer[4096];
+
+  SECTION("Returns different pointer") {
+    MemoryPool pool(buffer, sizeof(buffer));
+
+    VariantSlot* s1 = pool.allocVariant();
+    REQUIRE(s1 != 0);
+    VariantSlot* s2 = pool.allocVariant();
+    REQUIRE(s2 != 0);
+
+    REQUIRE(s1 != s2);
+  }
+
+  SECTION("Returns aligned pointers") {
+    MemoryPool pool(buffer, sizeof(buffer));
+
+    REQUIRE(isAligned(pool.allocVariant()));
+    REQUIRE(isAligned(pool.allocVariant()));
+  }
+
+  SECTION("Returns zero if capacity is 0") {
+    MemoryPool pool(buffer, 0);
+
+    REQUIRE(pool.allocVariant() == 0);
+  }
+
+  SECTION("Returns zero if buffer is null") {
+    MemoryPool pool(0, sizeof(buffer));
+
+    REQUIRE(pool.allocVariant() == 0);
+  }
+
+  SECTION("Returns zero if capacity is insufficient") {
+    MemoryPool pool(buffer, sizeof(VariantSlot));
+
+    pool.allocVariant();
+
+    REQUIRE(pool.allocVariant() == 0);
+  }
+}