diff --git a/dinkyecs.hpp b/dinkyecs.hpp
index 9e8011c..2690379 100644
--- a/dinkyecs.hpp
+++ b/dinkyecs.hpp
@@ -5,6 +5,9 @@
 #include <typeinfo>
 #include <unordered_map>
 #include <any>
+#include <tuple>
+#include <queue>
+
 
 namespace DinkyECS {
 
@@ -12,10 +15,18 @@ namespace DinkyECS {
 
   typedef std::unordered_map<Entity, std::any> EntityMap;
 
+  struct Event {
+    int event = 0;
+    Entity entity = 0;
+  };
+
+  typedef std::queue<Event> EventQueue;
+
   struct World {
     unsigned long entity_count = 0;
     std::unordered_map<std::type_index, EntityMap> $components;
     std::unordered_map<std::type_index, std::any> $facts;
+    std::unordered_map<std::type_index, EventQueue> $events;
 
     Entity entity() {
       return ++entity_count;
@@ -26,6 +37,11 @@ namespace DinkyECS {
         return $components[std::type_index(typeid(Comp))];
       }
 
+    template <typename Comp>
+      EventQueue& queue_map_for() {
+        return $events[std::type_index(typeid(Comp))];
+      }
+
     template <typename Comp>
       void remove(Entity ent) {
         EntityMap &map = entity_map_for<Comp>();
@@ -81,16 +97,24 @@ namespace DinkyECS {
         }
       }
 
-    /*
     template<typename Comp>
-      void send(int event, std::any data) {
-
+      void send(int event, Entity entity) {
+        EventQueue &queue = queue_map_for<Comp>();
+        queue.push({event, entity});
       }
 
     template<typename Comp>
-      std::tuple<int, std::any data> recv() {
+      Event recv() {
+        EventQueue &queue = queue_map_for<Comp>();
+        Event evt = queue.front();
+        queue.pop();
+        return evt;
+      }
 
+    template<typename Comp>
+      bool has_event() {
+        EventQueue &queue = queue_map_for<Comp>();
+        return !queue.empty();
       }
-    */
   };
 }
diff --git a/status.txt b/status.txt
index 09f4767..226048f 100644
--- a/status.txt
+++ b/status.txt
@@ -7,6 +7,7 @@ NOTES:
 
 TODO:
 
+* Rewrite collider to return a real struct not tuple.
 * Write a test that generates a ton of maps then confirms there's a path from one room to every other room?
 * Lua integration?
 
diff --git a/tests/dinkyecs.cpp b/tests/dinkyecs.cpp
index 3176e4a..363a29d 100644
--- a/tests/dinkyecs.cpp
+++ b/tests/dinkyecs.cpp
@@ -1,5 +1,5 @@
+#include <catch2/catch_test_macros.hpp>
 #include "dinkyecs.hpp"
-
 #include <iostream>
 #include <fmt/core.h>
 
@@ -23,6 +23,10 @@ struct Gravity {
   double level;
 };
 
+struct DaGUI {
+  int event;
+};
+
 /*
  * Using a function catches instances where I'm not copying
  * the data into the world.
@@ -35,7 +39,7 @@ void configure(DinkyECS::World &world, Entity &test) {
   world.set<Velocity>(test, {1,2});
 
   world.set<Position>(test2, {1,1});
-  world.set<Velocity>(test2, {10,20});
+  world.set<Velocity>(test2, {9,19});
 
   println("---- Setting up the player as a fact in the system.");
 
@@ -55,62 +59,91 @@ void configure(DinkyECS::World &world, Entity &test) {
   world.set_the<Gravity>({0.9});
 }
 
-int main() {
+TEST_CASE("confirm ECS system works", "[ecs]") {
   DinkyECS::World world;
   Entity test = world.entity();
 
   configure(world, test);
 
   Position &pos = world.get<Position>(test);
-  println("GOT POS x={}, y={}", pos.x, pos.y);
+  REQUIRE(pos.x == 10);
+  REQUIRE(pos.y == 20);
 
   Velocity &vel = world.get<Velocity>(test);
-  println("GOT VELOCITY x={}, y={}", vel.x, vel.y);
+  REQUIRE(vel.x == 1);
+  REQUIRE(vel.y == 2);
 
-  println("--- Position only system:");
   world.query<Position>([](const auto &ent, auto &pos) {
-      println("entity={}, pos.x={}, pos.y={}", ent, pos.x, pos.y);
+      REQUIRE(ent > 0);
+      REQUIRE(pos.x >= 0);
+      REQUIRE(pos.y >= 0);
   });
 
-  println("--- Velocity only system:");
-  world.query<Velocity>([](const auto &, auto &vel) {
-      println("vel.x={}, vel.y={}", vel.x, vel.y);
+  world.query<Velocity>([](const auto &ent, auto &vel) {
+      REQUIRE(ent > 0);
+      REQUIRE(vel.x >= 0);
+      REQUIRE(vel.y >= 0);
   });
 
   println("--- Manually get the velocity in position system:");
   world.query<Position>([&](const auto &ent, auto &pos) {
       Velocity &vel = world.get<Velocity>(ent);
-      println("entity={}, vel.x, vel.y, pos.x={}, pos.y={}", ent, vel.x, vel.y, pos.x, pos.y);
+
+      REQUIRE(ent > 0);
+      REQUIRE(pos.x >= 0);
+      REQUIRE(pos.y >= 0);
+      REQUIRE(ent > 0);
+      REQUIRE(vel.x >= 0);
+      REQUIRE(vel.y >= 0);
   });
 
   println("--- Query only entities with Position and Velocity:");
   world.query<Position, Velocity>([&](const auto &ent, auto &pos, auto &vel) {
       Gravity &grav = world.get_the<Gravity>();
-      println("grav={}, entity={}, vel.x, vel.y, pos.x={}, pos.y={}", grav.level, ent, vel.x, vel.y, pos.x, pos.y);
+      REQUIRE(grav.level <= 1.0f);
+      REQUIRE(grav.level > 0.5f);
+      REQUIRE(ent > 0);
+      REQUIRE(pos.x >= 0);
+      REQUIRE(pos.y >= 0);
+      REQUIRE(ent > 0);
+      REQUIRE(vel.x >= 0);
+      REQUIRE(vel.y >= 0);
   });
 
   // now remove Velocity
   world.remove<Velocity>(test);
+  REQUIRE_THROWS(world.get<Velocity>(test));
 
   println("--- After remove test, should only result in test2:");
   world.query<Position, Velocity>([&](const auto &ent, auto &pos, auto &vel) {
-      println("entity={}, vel.x, vel.y, pos.x={}, pos.y={}", ent, vel.x, vel.y, pos.x, pos.y);
+      REQUIRE(pos.x >= 0);
+      REQUIRE(pos.y >= 0);
   });
+}
+
+enum FakeEvent {
+  HIT_EVENT, MISS_EVENT
+};
+
+TEST_CASE("confirm that the event system works", "[ecs]") {
+  DinkyECS::World world;
+  DinkyECS::Entity gui_ent = world.entity();
+  DinkyECS::Entity player = world.entity();
+  DaGUI gui{384};
+
+  world.set<DaGUI>(gui_ent, gui);
+  DaGUI &gui_test = world.get<DaGUI>(gui_ent);
+  REQUIRE(gui.event == gui_test.event);
+
+  world.send<DaGUI>(FakeEvent::HIT_EVENT, player);
+
+  bool ready = world.has_event<DaGUI>();
+  REQUIRE(ready == true);
+
+  auto [event, entity] = world.recv<DaGUI>();
+  REQUIRE(event == FakeEvent::HIT_EVENT);
+  REQUIRE(entity == player);
 
-  // to avoid repeatedly getting the player just make a closure with it
-  // QUESTION: could I just capture it and not have the double function wrapping?
-  auto playerVsEnemies = [&]() {
-    auto& player = world.get_the<Player>(); // grabbed it
-    world.query<Position>([&](const auto &ent, auto &pos) {
-      if(player.eid != ent) {
-        println("{} is enemy attacking player {}", ent, player.name);
-      } else {
-        println("{} is player", player.name);
-      }
-    });
-  };
-
-  playerVsEnemies();
-
-  return 0;
+  ready = world.has_event<DaGUI>();
+  REQUIRE(ready == false);
 }