1 files changed, 19 insertions, 2 deletions
diff --git a/core/src/test/java/coffee/liz/ecs/model/EntityTest.java b/core/src/test/java/coffee/liz/ecs/model/EntityTest.java
index bb17296..5be4cdb 100644
--- a/core/src/test/java/coffee/liz/ecs/model/EntityTest.java
+++ b/core/src/test/java/coffee/liz/ecs/model/EntityTest.java
@@ -9,7 +9,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import coffee.liz.ecs.events.ComponentAdded;
 import coffee.liz.ecs.events.ComponentRemoved;
 import coffee.liz.ecs.events.EntityEvent;
-import coffee.liz.ecs.events.Hook;
 
 import lombok.RequiredArgsConstructor;
 
@@ -21,6 +20,7 @@ import org.junit.jupiter.params.provider.MethodSource;
 import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
 import java.util.stream.Stream;
 
 final class EntityTest {
@@ -70,6 +70,23 @@ final class EntityTest {
     }
 
     @Test
+    public void replacingExistingComponentDoesNotEmitAddedEvent() {
+        final Entity entity = Entity.builder().id(18).build();
+        final AtomicInteger addedCount = new AtomicInteger(0);
+        final Consumer<EntityEvent> hook = entity.subscribe(event -> {
+            if (event instanceof ComponentAdded) {
+                addedCount.incrementAndGet();
+            }
+        });
+
+        entity.add(new AlphaComponent("initial"));
+        entity.add(new AlphaComponent("replacement"));
+
+        assertEquals(1, addedCount.get());
+        entity.unsubscribe(hook);
+    }
+
+    @Test
     public void removeClearsComponentPresence() {
         final Entity entity = Entity.builder().id(45).build();
         entity.add(new BetaComponent(2));
@@ -87,7 +104,7 @@ final class EntityTest {
         final AtomicInteger addedCount = new AtomicInteger(0);
         final AtomicInteger removedCount = new AtomicInteger(0);
 
-        final Hook<EntityEvent> hook = entity.subscribe(event -> {
+        final Consumer<EntityEvent> hook = entity.subscribe(event -> {
             if (event instanceof ComponentAdded) {
                 addedCount.incrementAndGet();
             }