diff --git a/src/fastcs/attributes.py b/src/fastcs/attributes.py
index ab0494e89..160360db4 100644
--- a/src/fastcs/attributes.py
+++ b/src/fastcs/attributes.py
@@ -187,11 +187,7 @@ def __init__(
         )
         self._process_callbacks: list[AttrCallback[T]] | None = None
         self._write_display_callbacks: list[AttrCallback[T]] | None = None
-
-        if handler is not None:
-            self._setter = handler
-        else:
-            self._setter = SimpleAttrHandler()
+        self._setter = handler
 
     async def process(self, value: T) -> None:
         await self.process_without_display_update(value)
@@ -221,7 +217,7 @@ def add_write_display_callback(self, callback: AttrCallback[T]) -> None:
         self._write_display_callbacks.append(callback)
 
     @property
-    def sender(self) -> AttrHandlerW:
+    def sender(self) -> AttrHandlerW | None:
         return self._setter
 
 
@@ -241,7 +237,7 @@ def __init__(
             datatype,  # type: ignore
             access_mode,
             group=group,
-            handler=handler,
+            handler=handler if handler else SimpleAttrHandler(),
             initial_value=initial_value,
             description=description,
         )
diff --git a/tests/example_p4p_ioc.py b/tests/example_p4p_ioc.py
index 5fff09915..d7ce94745 100644
--- a/tests/example_p4p_ioc.py
+++ b/tests/example_p4p_ioc.py
@@ -3,7 +3,7 @@
 
 import numpy as np
 
-from fastcs.attributes import AttrR, AttrRW, AttrW
+from fastcs.attributes import AttrHandlerW, AttrR, AttrRW, AttrW
 from fastcs.controller import Controller, SubController
 from fastcs.datatypes import Bool, Enum, Float, Int, Table, Waveform
 from fastcs.launch import FastCS
@@ -14,6 +14,11 @@
 from fastcs.wrappers import command, scan
 
 
+class SimpleAttributeSetter(AttrHandlerW):
+    async def put(self, attr, value):
+        await attr.update_display_without_process(value)
+
+
 class FEnum(enum.Enum):
     A = 0
     B = 1
@@ -25,7 +30,7 @@ class FEnum(enum.Enum):
 class ParentController(Controller):
     description = "some controller"
     a: AttrRW = AttrRW(Int(max=400_000, max_alarm=40_000))
-    b: AttrW = AttrW(Float(min=-1, min_alarm=-0.5))
+    b: AttrW = AttrW(Float(min=-1, min_alarm=-0.5), handler=SimpleAttributeSetter())
 
     table: AttrRW = AttrRW(
         Table([("A", np.int32), ("B", "i"), ("C", "?"), ("D", np.float64)])
@@ -34,7 +39,7 @@ class ParentController(Controller):
 
 class ChildController(SubController):
     fail_on_next_e = True
-    c: AttrW = AttrW(Int())
+    c: AttrW = AttrW(Int(), handler=SimpleAttributeSetter())
 
     @command()
     async def d(self):
diff --git a/tests/test_attribute.py b/tests/test_attribute.py
index 473501a75..325fca792 100644
--- a/tests/test_attribute.py
+++ b/tests/test_attribute.py
@@ -3,7 +3,13 @@
 import pytest
 from pytest_mock import MockerFixture
 
-from fastcs.attributes import AttrHandlerR, AttrHandlerRW, AttrR, AttrRW, AttrW
+from fastcs.attributes import (
+    AttrHandlerR,
+    AttrHandlerRW,
+    AttrR,
+    AttrRW,
+    AttrW,
+)
 from fastcs.datatypes import Int, String
 
 
@@ -34,29 +40,23 @@ async def device_add():
     assert ui["number"] == 2
 
 
-@pytest.mark.asyncio
-async def test_simple_handler_w(mocker: MockerFixture):
-    attr = AttrW(Int())
-    update_display_mock = mocker.patch.object(attr, "update_display_without_process")
-
-    # This is called by the transport when it receives a put
-    await attr.sender.put(attr, 1)
-
-    # The callback to update the transport display should be called
-    update_display_mock.assert_called_once_with(1)
-
-
 @pytest.mark.asyncio
 async def test_simple_handler_rw(mocker: MockerFixture):
     attr = AttrRW(Int())
-    update_display_mock = mocker.patch.object(attr, "update_display_without_process")
-    set_mock = mocker.patch.object(attr, "set")
 
+    attr.update_display_without_process = mocker.MagicMock(
+        wraps=attr.update_display_without_process
+    )
+    attr.set = mocker.MagicMock(wraps=attr.set)
+
+    assert attr.sender
+    # This is called by the transport when it receives a put
     await attr.sender.put(attr, 1)
 
-    update_display_mock.assert_called_once_with(1)
     # The Sender of the attribute should just set the value on the attribute
-    set_mock.assert_awaited_once_with(1)
+    attr.update_display_without_process.assert_called_once_with(1)
+    attr.set.assert_called_once_with(1)
+    assert attr.get() == 1
 
 
 class SimpleUpdater(AttrHandlerR):