Properly link flecs library

engine/libs/flecs/test/api/src/Singleton.c

@@ -0,0 +1,91 @@
+#include <api.h>
+
+void Singleton_add_singleton(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_TAG(world, TagA);
+
+    test_assert(!ecs_has(world, TagA, TagA));
+
+    ecs_singleton_add(world, TagA);
+
+    test_assert(ecs_has(world, TagA, TagA));
+
+    ecs_fini(world);
+}
+
+void Singleton_remove_singleton(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_TAG(world, TagA);
+
+    test_assert(!ecs_has(world, TagA, TagA));
+
+    ecs_singleton_add(world, TagA);
+
+    test_assert(ecs_has(world, TagA, TagA));
+
+    ecs_singleton_remove(world, TagA);
+
+    test_assert(!ecs_has(world, TagA, TagA));
+
+    ecs_fini(world);
+}
+
+void Singleton_set_get_singleton(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_COMPONENT(world, Position);
+
+    ecs_singleton_set(world, Position, {10, 20});
+    
+    const Position *p = ecs_singleton_get(world, Position);
+    test_assert(p != NULL);
+    test_int(p->x, 10);
+    test_int(p->y, 20);
+
+    ecs_fini(world);
+}
+
+void Singleton_get_mut_singleton(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_COMPONENT(world, Position);
+
+    Position *p_mut = ecs_singleton_get_mut(world, Position);
+    p_mut->x = 10;
+    p_mut->y = 20;
+    
+    const Position *p = ecs_singleton_get(world, Position);
+    test_assert(p != NULL);
+    test_int(p->x, 10);
+    test_int(p->y, 20);
+
+    ecs_fini(world);
+}
+
+static
+void IncSingleton(ecs_iter_t *it) {
+    Position *p = ecs_field(it, Position, 1);
+    p->x ++;
+    p->y ++;
+}
+
+void Singleton_singleton_system(void) {
+    ecs_world_t *world = ecs_init();
+
+    ECS_COMPONENT(world, Position);
+
+    ECS_SYSTEM(world, IncSingleton, EcsOnUpdate, Position($));
+
+    ecs_singleton_set(world, Position, {10, 20});
+
+    ecs_progress(world, 0);
+
+    const Position *p = ecs_singleton_get(world, Position);
+    test_assert(p != NULL);
+    test_int(p->x, 11);
+    test_int(p->y, 21);
+
+    ecs_fini(world);    
+}