diff --git a/aiogram/fsm/scene.py b/aiogram/fsm/scene.py
index 66023e51..d39a4f01 100644
--- a/aiogram/fsm/scene.py
+++ b/aiogram/fsm/scene.py
@@ -126,6 +126,8 @@ class ObserverDecorator:
         )
 
     def _wrap_action(self, target: CallbackType) -> None:
+        assert self.action is not None, "Scene action is not specified"
+
         action = getattr(target, "__aiogram_action__", None)
         if action is None:
             action = defaultdict(dict)
diff --git a/tests/test_fsm/test_scene.py b/tests/test_fsm/test_scene.py
new file mode 100644
index 00000000..b4ce48dd
--- /dev/null
+++ b/tests/test_fsm/test_scene.py
@@ -0,0 +1,150 @@
+import pytest
+
+from aiogram import F
+from aiogram.fsm.scene import (
+    on,
+    ObserverMarker,
+    ObserverDecorator,
+    After,
+    SceneAction,
+    _empty_handler,
+)
+
+
+class TestOnMarker:
+    @pytest.mark.parametrize(
+        "marker_name",
+        [
+            "message",
+            "edited_message",
+            "channel_post",
+            "edited_channel_post",
+            "inline_query",
+            "chosen_inline_result",
+            "callback_query",
+            "shipping_query",
+            "pre_checkout_query",
+            "poll",
+            "poll_answer",
+            "my_chat_member",
+            "chat_member",
+            "chat_join_request",
+        ],
+    )
+    def test_marker_name(self, marker_name: str):
+        attr = getattr(on, marker_name)
+        assert isinstance(attr, ObserverMarker)
+        assert attr.name == marker_name
+
+
+async def test_empty_handler():
+    result = await _empty_handler()
+    assert result is None
+
+
+class TestAfter:
+    def test_exit(self):
+        after = After.exit()
+        assert after is not None
+        assert after.action == SceneAction.exit
+        assert after.scene is None
+
+    def test_back(self):
+        after = After.back()
+        assert after is not None
+        assert after.action == SceneAction.back
+        assert after.scene is None
+
+    def test_goto(self):
+        after = After.goto("test")
+        assert after is not None
+        assert after.action == SceneAction.enter
+        assert after.scene == "test"
+
+
+class TestObserverMarker:
+    def test_decorator(self):
+        marker = ObserverMarker("test")
+        decorator = marker(F.test, after=After.back())
+        assert isinstance(decorator, ObserverDecorator)
+        assert decorator.name == "test"
+        assert len(decorator.filters) == 1
+        assert decorator.action is None
+        assert decorator.after is not None
+
+    def test_enter(self):
+        marker = ObserverMarker("test")
+        decorator = marker.enter(F.test)
+        assert isinstance(decorator, ObserverDecorator)
+        assert decorator.name == "test"
+        assert len(decorator.filters) == 1
+        assert decorator.action == SceneAction.enter
+        assert decorator.after is None
+
+    def test_leave(self):
+        marker = ObserverMarker("test")
+        decorator = marker.leave()
+        assert isinstance(decorator, ObserverDecorator)
+        assert decorator.name == "test"
+        assert len(decorator.filters) == 0
+        assert decorator.action == SceneAction.leave
+        assert decorator.after is None
+
+    def test_exit(self):
+        marker = ObserverMarker("test")
+        decorator = marker.exit()
+        assert isinstance(decorator, ObserverDecorator)
+        assert decorator.name == "test"
+        assert len(decorator.filters) == 0
+        assert decorator.action == SceneAction.exit
+        assert decorator.after is None
+
+    def test_back(self):
+        marker = ObserverMarker("test")
+        decorator = marker.back()
+        assert isinstance(decorator, ObserverDecorator)
+        assert decorator.name == "test"
+        assert len(decorator.filters) == 0
+        assert decorator.action == SceneAction.back
+        assert decorator.after is None
+
+
+class TestObserverDecorator:
+    def test_wrap_something(self):
+        decorator = ObserverDecorator("test", F.test)
+
+        with pytest.raises(TypeError):
+            decorator("test")
+
+    def test_wrap_handler(self):
+        decorator = ObserverDecorator("test", F.test)
+
+        def handler():
+            pass
+
+        wrapped = decorator(handler)
+
+        assert wrapped is not None
+        assert hasattr(wrapped, "__aiogram_handler__")
+        assert isinstance(wrapped.__aiogram_handler__, list)
+        assert len(wrapped.__aiogram_handler__) == 1
+
+        wrapped2 = decorator(handler)
+
+        assert len(wrapped2.__aiogram_handler__) == 2
+
+    def test_wrap_action(self):
+        decorator = ObserverDecorator("test", F.test)
+
+        def handler():
+            pass
+
+        wrapped = decorator(handler)
+        assert wrapped is not None
+        assert not hasattr(wrapped, "__aiogram_handler__")
+        assert hasattr(wrapped, "__aiogram_action__")
+
+        assert isinstance(wrapped.__aiogram_action__, dict)
+        assert len(wrapped.__aiogram_action__) == 1
+        assert "test" in wrapped.__aiogram_action__
+        assert wrapped.__aiogram_action__["test"]