feat: add world.Count method

world.go

@@ -318,6 +318,11 @@ func (world *World) SetEntityName(entityId EntityId, name string) {
 	world.entitiesNames[entityName] = entityId
 }
 
+// Count returns the number of entities in World.
+func (world *World) Count() int {
+	return len(world.entities)
+}
+
 func stringToEntityName(name string) entityName {
 	var nameByte entityName
 	copy(nameByte[:], name)

world_test.go

@@ -359,3 +359,21 @@ func TestWorld_GetEntityName(t *testing.T) {
 		t.Errorf("world.GetEntityName does not return empty string for entityId 0")
 	}
 }
+
+func TestWorld_Count(t *testing.T) {
+	world := CreateWorld(1024)
+
+	if world.Count() != 0 {
+		t.Errorf("world.Count should return 0 if the world is empty")
+	}
+
+	entities := make([]EntityId, TEST_ENTITY_NUMBER)
+
+	for i := 0; i < TEST_ENTITY_NUMBER; i++ {
+		entities[i] = world.CreateEntity(fmt.Sprint(i))
+	}
+
+	if world.Count() != TEST_ENTITY_NUMBER {
+		t.Errorf("world.Count returned %d after inserting %d entities", world.Count(), TEST_ENTITY_NUMBER)
+	}
+}