WIP: improvements and new features

test/tag_handler.cpp

@@ -0,0 +1,46 @@
+#include <gtest/gtest.h>
+#include <tag_handler.hpp>
+
+TEST(TagHandler, Functionalities) {
+    using TagHandler = entt::TagHandler<unsigned int, int>;
+
+    TagHandler handler;
+
+    ASSERT_TRUE(handler.empty());
+    ASSERT_EQ(handler.size(), 0u);
+    ASSERT_EQ(handler.begin(), handler.end());
+    ASSERT_FALSE(handler.has(0));
+    ASSERT_FALSE(handler.has(1));
+
+    ASSERT_EQ(handler.construct(0, 42), 42);
+
+    ASSERT_FALSE(handler.empty());
+    ASSERT_EQ(handler.size(), 1u);
+    ASSERT_NE(handler.begin(), handler.end());
+    ASSERT_TRUE(handler.has(0));
+    ASSERT_FALSE(handler.has(1));
+
+    auto begin = handler.begin();
+
+    ASSERT_EQ(*begin, 42);
+    ASSERT_EQ(handler.get(0), 42);
+    ASSERT_EQ(++begin, handler.end());
+
+    handler.destroy(0);
+
+    ASSERT_TRUE(handler.empty());
+    ASSERT_EQ(handler.size(), 0u);
+    ASSERT_EQ(handler.begin(), handler.end());
+    ASSERT_FALSE(handler.has(0));
+    ASSERT_FALSE(handler.has(1));
+
+    ASSERT_EQ(handler.construct(0, 12), 12);
+
+    handler.reset();
+
+    ASSERT_TRUE(handler.empty());
+    ASSERT_EQ(handler.size(), 0u);
+    ASSERT_EQ(handler.begin(), handler.end());
+    ASSERT_FALSE(handler.has(0));
+    ASSERT_FALSE(handler.has(1));
+}