diff --git a/aiogram/dispatcher/event/observer.py b/aiogram/dispatcher/event/observer.py
index 096a2254..cf9d00aa 100644
--- a/aiogram/dispatcher/event/observer.py
+++ b/aiogram/dispatcher/event/observer.py
@@ -70,18 +70,18 @@ class TelegramEventObserver(EventObserver):
         self.filters: List[Type[BaseFilter]] = []
 
     def bind_filter(self, bound_filter: Type[BaseFilter]) -> None:
-        if not isinstance(bound_filter, BaseFilter):
-            pass
+        if not issubclass(bound_filter, BaseFilter):
+            raise TypeError(
+                "bound_filter() argument 'bound_filter' must be subclass of BaseFilter"
+            )
         self.filters.append(bound_filter)
 
     def _resolve_filters_chain(self):
         registry: List[FilterType] = []
-        routers: List[Router] = []
 
         router = self.router
-        while router and router not in routers:
+        while router:
             observer = router.observers[self.event_name]
-            routers.append(router)
             router = router.parent_router
 
             for filter_ in observer.filters:
diff --git a/aiogram/dispatcher/filters/base.py b/aiogram/dispatcher/filters/base.py
index e49db340..cab3c4ec 100644
--- a/aiogram/dispatcher/filters/base.py
+++ b/aiogram/dispatcher/filters/base.py
@@ -16,7 +16,7 @@ class BaseFilter(ABC, BaseModel):
         @abstractmethod
         async def __call__(
             self, *args: Any, **kwargs: Any
-        ) -> Callable[[Any], Awaitable[Union[bool, Dict[str, Any]]]]:
+        ) -> Union[bool, Dict[str, Any]]:
             pass
 
     def __await__(self):
diff --git a/tests/test_dispatcher/test_event/test_observer.py b/tests/test_dispatcher/test_event/test_observer.py
index 651387dd..0b21b62e 100644
--- a/tests/test_dispatcher/test_event/test_observer.py
+++ b/tests/test_dispatcher/test_event/test_observer.py
@@ -1,10 +1,11 @@
 import functools
-from typing import Any, NoReturn
+from typing import Any, Awaitable, Callable, Dict, NoReturn, Union
 
 import pytest
-
 from aiogram.dispatcher.event.handler import HandlerObject
-from aiogram.dispatcher.event.observer import EventObserver, SkipHandler
+from aiogram.dispatcher.event.observer import EventObserver, SkipHandler, TelegramEventObserver
+from aiogram.dispatcher.filters.base import BaseFilter
+from aiogram.dispatcher.router import Router
 
 
 async def my_handler(event: Any, index: int = 0) -> Any:
@@ -106,3 +107,65 @@ class TestEventObserver:
 
         results = [result async for result in observer.trigger(42)]
         assert results == [((42,), {"b": 2})]
+
+
+class TestTelegramEventObserver:
+    def test_bind_filter(self):
+        event_observer = TelegramEventObserver(Router(), "test")
+        with pytest.raises(TypeError):
+            event_observer.bind_filter(object)  # type: ignore
+
+        class MyFilter(BaseFilter):
+            async def __call__(
+                self, *args: Any, **kwargs: Any
+            ) -> Callable[[Any], Awaitable[Union[bool, Dict[str, Any]]]]:
+                pass
+
+        event_observer.bind_filter(MyFilter)
+        assert event_observer.filters
+        assert event_observer.filters[0] == MyFilter
+
+    def test_resolve_filters_chain(self):
+        router1 = Router()
+        router2 = Router()
+        router3 = Router()
+        router1.include_router(router2)
+        router2.include_router(router3)
+
+        class MyFilter1(BaseFilter):
+            test: str
+
+            async def __call__(self, *args: Any, **kwargs: Any) -> Union[bool, Dict[str, Any]]:
+                return True
+
+        class MyFilter2(MyFilter1):
+            pass
+
+        class MyFilter3(MyFilter1):
+            pass
+
+        router1.message_handler.bind_filter(MyFilter1)
+        router1.message_handler.bind_filter(MyFilter2)
+        router2.message_handler.bind_filter(MyFilter2)
+        router3.message_handler.bind_filter(MyFilter3)
+
+        filters_chain1 = list(router1.message_handler._resolve_filters_chain())
+        filters_chain2 = list(router2.message_handler._resolve_filters_chain())
+        filters_chain3 = list(router3.message_handler._resolve_filters_chain())
+
+        assert filters_chain1 == [MyFilter1, MyFilter2]
+        assert filters_chain2 == [MyFilter2, MyFilter1]
+        assert filters_chain3 == [MyFilter3, MyFilter2, MyFilter1]
+
+    def test_resolve_filters(self):
+        pass
+
+    def test_register(self):
+        pass
+
+    def test_register_decorator(self):
+        pass
+
+    @pytest.mark.asyncio
+    async def test_trigger(self):
+        pass