diff --git a/tests/iot/modules/test_ambientlight.py b/tests/iot/modules/test_ambientlight.py
index ff2bd92c2..9abae4054 100644
--- a/tests/iot/modules/test_ambientlight.py
+++ b/tests/iot/modules/test_ambientlight.py
@@ -8,7 +8,7 @@
 
 
 @dimmer_iot
-def test_ambientlight_getters(dev: IotDimmer):
+def test_ambientlight_getters(dev: IotDimmer) -> None:
     assert Module.IotAmbientLight in dev.modules
     ambientlight: AmbientLight = dev.modules[Module.IotAmbientLight]
 
@@ -22,7 +22,7 @@ def test_ambientlight_getters(dev: IotDimmer):
 
 
 @dimmer_iot
-async def test_ambientlight_setters(dev: IotDimmer, mocker: MockerFixture):
+async def test_ambientlight_setters(dev: IotDimmer, mocker: MockerFixture) -> None:
     ambientlight: AmbientLight = dev.modules[Module.IotAmbientLight]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -36,7 +36,7 @@ async def test_ambientlight_setters(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-def test_ambientlight_feature(dev: IotDimmer):
+def test_ambientlight_feature(dev: IotDimmer) -> None:
     assert Module.IotAmbientLight in dev.modules
     ambientlight: AmbientLight = dev.modules[Module.IotAmbientLight]
 
diff --git a/tests/iot/modules/test_cloud.py b/tests/iot/modules/test_cloud.py
index ec7f8f834..9c4aca98c 100644
--- a/tests/iot/modules/test_cloud.py
+++ b/tests/iot/modules/test_cloud.py
@@ -4,7 +4,7 @@
 
 
 @device_iot
-def test_cloud(dev: Device):
+def test_cloud(dev: Device) -> None:
     cloud = dev.modules.get(Module.IotCloud)
     assert cloud
     info = cloud.info
diff --git a/tests/iot/modules/test_dimmer.py b/tests/iot/modules/test_dimmer.py
index e4b267610..a5a009045 100644
--- a/tests/iot/modules/test_dimmer.py
+++ b/tests/iot/modules/test_dimmer.py
@@ -14,7 +14,7 @@
 
 
 @dimmer_iot
-def test_dimmer_getters(dev: IotDimmer):
+def test_dimmer_getters(dev: IotDimmer) -> None:
     assert Module.IotDimmer in dev.modules
     dimmer: Dimmer = dev.modules[Module.IotDimmer]
 
@@ -27,7 +27,7 @@ def test_dimmer_getters(dev: IotDimmer):
 
 
 @dimmer_iot
-async def test_dimmer_setters(dev: IotDimmer, mocker: MockerFixture):
+async def test_dimmer_setters(dev: IotDimmer, mocker: MockerFixture) -> None:
     dimmer: Dimmer = dev.modules[Module.IotDimmer]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -65,7 +65,7 @@ async def test_dimmer_setters(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_dimmer_setter_min(dev: IotDimmer, mocker: MockerFixture):
+async def test_dimmer_setter_min(dev: IotDimmer, mocker: MockerFixture) -> None:
     dimmer: Dimmer = dev.modules[Module.IotDimmer]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -103,7 +103,7 @@ async def test_dimmer_setter_min(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_dimmer_setter_max(dev: IotDimmer, mocker: MockerFixture):
+async def test_dimmer_setter_max(dev: IotDimmer, mocker: MockerFixture) -> None:
     dimmer: Dimmer = dev.modules[Module.IotDimmer]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -141,7 +141,7 @@ async def test_dimmer_setter_max(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_dimmer_setters_min_oob(dev: IotDimmer, mocker: MockerFixture):
+async def test_dimmer_setters_min_oob(dev: IotDimmer, mocker: MockerFixture) -> None:
     dimmer: Dimmer = dev.modules[Module.IotDimmer]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -173,7 +173,7 @@ async def test_dimmer_setters_min_oob(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_dimmer_setters_max_oob(dev: IotDimmer, mocker: MockerFixture):
+async def test_dimmer_setters_max_oob(dev: IotDimmer, mocker: MockerFixture) -> None:
     dimmer: Dimmer = dev.modules[Module.IotDimmer]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
diff --git a/tests/iot/modules/test_emeter.py b/tests/iot/modules/test_emeter.py
index 54fd02b2e..160cd5a5d 100644
--- a/tests/iot/modules/test_emeter.py
+++ b/tests/iot/modules/test_emeter.py
@@ -12,7 +12,7 @@
 
 from kasa import Device, DeviceType, EmeterStatus, Module
 from kasa.interfaces.energy import Energy
-from kasa.iot import IotStrip
+from kasa.iot import IotDevice, IotStrip
 from kasa.iot.modules.emeter import Emeter
 from tests.conftest import has_emeter_iot, no_emeter_iot
 
@@ -37,22 +37,22 @@
 
 
 @no_emeter_iot
-async def test_no_emeter(dev):
+async def test_no_emeter(dev: IotDevice) -> None:
     assert not dev.has_emeter
 
     with pytest.raises(AttributeError):
-        await dev.get_emeter_realtime()
+        await dev.get_emeter_realtime()  # type: ignore[attr-defined]
 
     with pytest.raises(AttributeError):
-        await dev.get_emeter_daily()
+        await dev.get_emeter_daily()  # type: ignore[attr-defined]
     with pytest.raises(AttributeError):
-        await dev.get_emeter_monthly()
+        await dev.get_emeter_monthly()  # type: ignore[attr-defined]
     with pytest.raises(AttributeError):
-        await dev.erase_emeter_stats()
+        await dev.erase_emeter_stats()  # type: ignore[attr-defined]
 
 
 @has_emeter_iot
-async def test_get_emeter_realtime(dev):
+async def test_get_emeter_realtime(dev: IotDevice) -> None:
     emeter = dev.modules[Module.Energy]
 
     current_emeter = await emeter.get_status()
@@ -65,7 +65,7 @@ async def test_get_emeter_realtime(dev):
 
 @has_emeter_iot
 @pytest.mark.requires_dummy
-async def test_get_emeter_daily(dev):
+async def test_get_emeter_daily(dev: IotDevice) -> None:
     emeter = dev.modules[Module.Energy]
 
     assert await emeter.get_daily_stats(year=1900, month=1) == {}
@@ -85,7 +85,7 @@ async def test_get_emeter_daily(dev):
 
 @has_emeter_iot
 @pytest.mark.requires_dummy
-async def test_get_emeter_monthly(dev):
+async def test_get_emeter_monthly(dev: IotDevice) -> None:
     emeter = dev.modules[Module.Energy]
 
     assert await emeter.get_monthly_stats(year=1900) == {}
@@ -104,7 +104,7 @@ async def test_get_emeter_monthly(dev):
 
 
 @has_emeter_iot
-async def test_emeter_status(dev):
+async def test_emeter_status(dev: IotDevice) -> None:
     emeter = dev.modules[Module.Energy]
 
     d = await emeter.get_status()
@@ -126,21 +126,21 @@ async def test_emeter_status(dev):
 
 @pytest.mark.skip("not clearing your stats..")
 @has_emeter_iot
-async def test_erase_emeter_stats(dev):
+async def test_erase_emeter_stats(dev: IotDevice) -> None:
     emeter = dev.modules[Module.Energy]
 
     await emeter.erase_emeter()
 
 
 @has_emeter_iot
-async def test_current_consumption(dev):
+async def test_current_consumption(dev: IotDevice) -> None:
     emeter = dev.modules[Module.Energy]
     x = emeter.current_consumption
     assert isinstance(x, float)
     assert x >= 0.0
 
 
-async def test_emeterstatus_missing_current():
+async def test_emeterstatus_missing_current() -> None:
     """KL125 does not report 'current' for emeter."""
     regular = EmeterStatus(
         {"err_code": 0, "power_mw": 0, "total_wh": 13, "current_ma": 123}
@@ -154,13 +154,13 @@ async def test_emeterstatus_missing_current():
     assert missing_current["current"] is None
 
 
-async def test_emeter_daily():
+async def test_emeter_daily() -> None:
     """Test fetching the emeter for today.
 
     This test uses inline data since the fixtures
     will not have data for the current day.
     """
-    emeter_data = {
+    emeter_data: dict = {
         "get_daystat": {
             "day_list": [{"day": 1, "energy_wh": 8, "month": 1, "year": 2023}],
             "err_code": 0,
@@ -181,7 +181,7 @@ def data(self):
 
 
 @has_emeter_iot
-async def test_supported(dev: Device):
+async def test_supported(dev: Device) -> None:
     energy_module = dev.modules.get(Module.Energy)
     assert energy_module
 
diff --git a/tests/iot/modules/test_homekit.py b/tests/iot/modules/test_homekit.py
index 29436785f..c542df4e0 100644
--- a/tests/iot/modules/test_homekit.py
+++ b/tests/iot/modules/test_homekit.py
@@ -10,7 +10,7 @@
 
 
 @device_iot
-def test_homekit_getters(dev: IotDevice):
+def test_homekit_getters(dev: IotDevice) -> None:
     # HomeKit can be present on any IOT device
     if Module.IotHomeKit not in dev.modules:
         pytest.skip("HomeKit module not present on this device")
@@ -31,7 +31,7 @@ def test_homekit_getters(dev: IotDevice):
 
 
 @device_iot
-def test_homekit_feature(dev: IotDevice):
+def test_homekit_feature(dev: IotDevice) -> None:
     if Module.IotHomeKit not in dev.modules:
         pytest.skip("HomeKit module not present on this device")
     homekit: HomeKit = dev.modules[Module.IotHomeKit]
@@ -45,7 +45,7 @@ def test_homekit_feature(dev: IotDevice):
 
 
 @device_iot
-def test_initialize_features_skips_when_no_data(dev: IotDevice):
+def test_initialize_features_skips_when_no_data(dev: IotDevice) -> None:
     if Module.IotHomeKit not in dev.modules:
         pytest.skip("HomeKit module not present on this device")
     homekit: HomeKit = dev.modules[Module.IotHomeKit]
diff --git a/tests/iot/modules/test_motion.py b/tests/iot/modules/test_motion.py
index 2d1ccbcc7..e0ed8c2e1 100644
--- a/tests/iot/modules/test_motion.py
+++ b/tests/iot/modules/test_motion.py
@@ -9,7 +9,7 @@
 
 
 @dimmer_iot
-def test_motion_getters(dev: IotDimmer):
+def test_motion_getters(dev: IotDimmer) -> None:
     assert Module.IotMotion in dev.modules
     motion: Motion = dev.modules[Module.IotMotion]
 
@@ -19,7 +19,7 @@ def test_motion_getters(dev: IotDimmer):
 
 
 @dimmer_iot
-async def test_motion_setters(dev: IotDimmer, mocker: MockerFixture):
+async def test_motion_setters(dev: IotDimmer, mocker: MockerFixture) -> None:
     motion: Motion = dev.modules[Module.IotMotion]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -33,7 +33,7 @@ async def test_motion_setters(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_motion_range(dev: IotDimmer, mocker: MockerFixture):
+async def test_motion_range(dev: IotDimmer, mocker: MockerFixture) -> None:
     motion: Motion = dev.modules[Module.IotMotion]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -47,7 +47,7 @@ async def test_motion_range(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_motion_range_from_string(dev: IotDimmer, mocker: MockerFixture):
+async def test_motion_range_from_string(dev: IotDimmer, mocker: MockerFixture) -> None:
     motion: Motion = dev.modules[Module.IotMotion]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -74,7 +74,7 @@ async def test_motion_range_from_string(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_motion_threshold(dev: IotDimmer, mocker: MockerFixture):
+async def test_motion_threshold(dev: IotDimmer, mocker: MockerFixture) -> None:
     motion: Motion = dev.modules[Module.IotMotion]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -97,7 +97,7 @@ async def test_motion_threshold(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-async def test_motion_realtime(dev: IotDimmer, mocker: MockerFixture):
+async def test_motion_realtime(dev: IotDimmer, mocker: MockerFixture) -> None:
     motion: Motion = dev.modules[Module.IotMotion]
     query_helper = mocker.patch("kasa.iot.IotDimmer._query_helper")
 
@@ -106,7 +106,7 @@ async def test_motion_realtime(dev: IotDimmer, mocker: MockerFixture):
 
 
 @dimmer_iot
-def test_motion_feature(dev: IotDimmer):
+def test_motion_feature(dev: IotDimmer) -> None:
     assert Module.IotMotion in dev.modules
     motion: Motion = dev.modules[Module.IotMotion]
 
diff --git a/tests/iot/modules/test_schedule.py b/tests/iot/modules/test_schedule.py
index 4a4ffdee6..c65cb36f3 100644
--- a/tests/iot/modules/test_schedule.py
+++ b/tests/iot/modules/test_schedule.py
@@ -8,7 +8,7 @@
 
 @device_iot
 @pytest.mark.xdist_group(name="caplog")
-def test_schedule(dev: Device, caplog: pytest.LogCaptureFixture):
+def test_schedule(dev: Device, caplog: pytest.LogCaptureFixture) -> None:
     schedule = dev.modules.get(Module.IotSchedule)
     assert schedule
     if rules := schedule.rules:
diff --git a/tests/iot/modules/test_usage.py b/tests/iot/modules/test_usage.py
index 7b2c0eed6..e180b01b7 100644
--- a/tests/iot/modules/test_usage.py
+++ b/tests/iot/modules/test_usage.py
@@ -4,10 +4,10 @@
 from kasa.iot.modules import Usage
 
 
-def test_usage_convert_stat_data():
-    usage = Usage(None, module="usage")
+def test_usage_convert_stat_data() -> None:
+    usage = Usage(Mock(), module="usage")
 
-    test_data = []
+    test_data: list[dict[str, int]] = []
     assert usage._convert_stat_data(test_data, "day") == {}
 
     test_data = [
@@ -24,13 +24,13 @@ def test_usage_convert_stat_data():
     assert v == 30
 
 
-def test_usage_today():
+def test_usage_today() -> None:
     """Test fetching the usage for today.
 
     This test uses inline data since the fixtures
     will not have data for the current day.
     """
-    emeter_data = {
+    emeter_data: dict = {
         "get_daystat": {
             "day_list": [],
             "err_code": 0,
@@ -55,13 +55,13 @@ def data(self):
     assert usage.usage_today == 500
 
 
-def test_usage_this_month():
+def test_usage_this_month() -> None:
     """Test fetching the usage for this month.
 
     This test uses inline data since the fixtures
     will not have data for the current month.
     """
-    emeter_data = {
+    emeter_data: dict = {
         "get_monthstat": {
             "month_list": [],
             "err_code": 0,
diff --git a/tests/iot/test_iotbulb.py b/tests/iot/test_iotbulb.py
index 4d40dff67..870efe20f 100644
--- a/tests/iot/test_iotbulb.py
+++ b/tests/iot/test_iotbulb.py
@@ -3,6 +3,7 @@
 import re
 
 import pytest
+from pytest_mock import MockerFixture
 from voluptuous import (
     All,
     Boolean,
@@ -27,7 +28,7 @@
 
 
 @bulb_iot
-async def test_bulb_sysinfo(dev: Device):
+async def test_bulb_sysinfo(dev: Device) -> None:
     assert dev.sys_info is not None
     SYSINFO_SCHEMA_BULB(dev.sys_info)
 
@@ -35,19 +36,21 @@ async def test_bulb_sysinfo(dev: Device):
 
 
 @bulb_iot
-async def test_light_state_without_update(dev: IotBulb, monkeypatch):
+async def test_light_state_without_update(
+    dev: IotBulb, monkeypatch: pytest.MonkeyPatch
+) -> None:
     monkeypatch.setitem(dev._last_update["system"]["get_sysinfo"], "light_state", None)
     with pytest.raises(KasaException):
         print(dev.light_state)
 
 
 @bulb_iot
-async def test_get_light_state(dev: IotBulb):
+async def test_get_light_state(dev: IotBulb) -> None:
     LIGHT_STATE_SCHEMA(await dev.get_light_state())
 
 
 @color_bulb_iot
-async def test_set_hsv_transition(dev: IotBulb, mocker):
+async def test_set_hsv_transition(dev: IotBulb, mocker: MockerFixture) -> None:
     set_light_state = mocker.patch("kasa.iot.IotBulb._set_light_state")
     light = dev.modules.get(Module.Light)
     assert light
@@ -60,7 +63,7 @@ async def test_set_hsv_transition(dev: IotBulb, mocker):
 
 
 @bulb_iot
-async def test_light_set_state(dev: IotBulb, mocker):
+async def test_light_set_state(dev: IotBulb, mocker: MockerFixture) -> None:
     """Testing setting LightState on the light module."""
     light = dev.modules.get(Module.Light)
     assert light
@@ -76,7 +79,7 @@ async def test_light_set_state(dev: IotBulb, mocker):
 
 
 @variable_temp_iot
-async def test_set_color_temp_transition(dev: IotBulb, mocker):
+async def test_set_color_temp_transition(dev: IotBulb, mocker: MockerFixture) -> None:
     set_light_state = mocker.patch("kasa.iot.IotBulb._set_light_state")
     light = dev.modules.get(Module.Light)
     assert light
@@ -87,7 +90,9 @@ async def test_set_color_temp_transition(dev: IotBulb, mocker):
 
 @variable_temp_iot
 @pytest.mark.xdist_group(name="caplog")
-async def test_unknown_temp_range(dev: IotBulb, monkeypatch, caplog):
+async def test_unknown_temp_range(
+    dev: IotBulb, monkeypatch: pytest.MonkeyPatch, caplog: pytest.LogCaptureFixture
+) -> None:
     monkeypatch.setitem(dev._sys_info, "model", "unknown bulb")
     light = dev.modules.get(Module.Light)
     assert light
@@ -99,7 +104,7 @@ async def test_unknown_temp_range(dev: IotBulb, monkeypatch, caplog):
 
 @dimmable_iot
 @turn_on
-async def test_dimmable_brightness(dev: IotBulb, turn_on):
+async def test_dimmable_brightness(dev: IotBulb, turn_on: bool) -> None:
     assert isinstance(dev, IotBulb | IotDimmer)
     light = dev.modules.get(Module.Light)
     assert light
@@ -119,7 +124,7 @@ async def test_dimmable_brightness(dev: IotBulb, turn_on):
 
 
 @bulb_iot
-async def test_turn_on_transition(dev: IotBulb, mocker):
+async def test_turn_on_transition(dev: IotBulb, mocker: MockerFixture) -> None:
     set_light_state = mocker.patch("kasa.iot.IotBulb._set_light_state")
     await dev.turn_on(transition=1000)
 
@@ -131,7 +136,9 @@ async def test_turn_on_transition(dev: IotBulb, mocker):
 
 
 @bulb_iot
-async def test_dimmable_brightness_transition(dev: IotBulb, mocker):
+async def test_dimmable_brightness_transition(
+    dev: IotBulb, mocker: MockerFixture
+) -> None:
     set_light_state = mocker.patch("kasa.iot.IotBulb._set_light_state")
     light = dev.modules.get(Module.Light)
     assert light
@@ -141,7 +148,7 @@ async def test_dimmable_brightness_transition(dev: IotBulb, mocker):
 
 
 @dimmable_iot
-async def test_invalid_brightness(dev: IotBulb):
+async def test_invalid_brightness(dev: IotBulb) -> None:
     assert dev._is_dimmable
     light = dev.modules.get(Module.Light)
     assert light
@@ -159,7 +166,7 @@ async def test_invalid_brightness(dev: IotBulb):
 
 
 @non_dimmable_iot
-async def test_non_dimmable(dev: IotBulb):
+async def test_non_dimmable(dev: IotBulb) -> None:
     assert not dev._is_dimmable
     light = dev.modules.get(Module.Light)
     assert light
@@ -171,8 +178,8 @@ async def test_non_dimmable(dev: IotBulb):
 
 @bulb_iot
 async def test_ignore_default_not_set_without_color_mode_change_turn_on(
-    dev: IotBulb, mocker
-):
+    dev: IotBulb, mocker: MockerFixture
+) -> None:
     query_helper = mocker.patch("kasa.iot.IotBulb._query_helper")
     # When turning back without settings, ignore default to restore the state
     await dev.turn_on()
@@ -185,7 +192,7 @@ async def test_ignore_default_not_set_without_color_mode_change_turn_on(
 
 
 @bulb_iot
-async def test_list_presets(dev: IotBulb):
+async def test_list_presets(dev: IotBulb) -> None:
     light_preset = dev.modules.get(Module.LightPreset)
     assert light_preset
     assert isinstance(light_preset, IotLightPresetModule)
@@ -206,7 +213,7 @@ async def test_list_presets(dev: IotBulb):
 
 
 @bulb_iot
-async def test_modify_preset(dev: IotBulb, mocker):
+async def test_modify_preset(dev: IotBulb, mocker: MockerFixture) -> None:
     """Verify that modifying preset calls the and exceptions are raised properly."""
     if (
         not (light_preset := dev.modules.get(Module.LightPreset))
@@ -254,7 +261,9 @@ async def test_modify_preset(dev: IotBulb, mocker):
         ),
     ],
 )
-async def test_modify_preset_payloads(dev: IotBulb, preset, payload, mocker):
+async def test_modify_preset_payloads(
+    dev: IotBulb, preset, payload, mocker: MockerFixture
+) -> None:
     """Test that modify preset payloads ignore none values."""
     if (
         not (light_preset := dev.modules.get(Module.LightPreset))
@@ -318,6 +327,6 @@ async def test_modify_preset_payloads(dev: IotBulb, preset, payload, mocker):
 
 
 @bulb_iot
-async def test_turn_on_behaviours(dev: IotBulb):
+async def test_turn_on_behaviours(dev: IotBulb) -> None:
     behavior = await dev.get_turn_on_behavior()
     assert behavior
diff --git a/tests/iot/test_iotdevice.py b/tests/iot/test_iotdevice.py
index 16dac35ff..19625a641 100644
--- a/tests/iot/test_iotdevice.py
+++ b/tests/iot/test_iotdevice.py
@@ -4,6 +4,7 @@
 from datetime import datetime
 
 import pytest
+from pytest_mock import MockerFixture
 from voluptuous import (
     REMOVE_EXTRA,
     All,
@@ -84,20 +85,20 @@ def check_mac(x):
 
 
 @device_iot
-async def test_state_info(dev):
+async def test_state_info(dev: IotDevice) -> None:
     assert isinstance(dev.state_information, dict)
 
 
 @pytest.mark.requires_dummy
 @device_iot
-async def test_invalid_connection(mocker, dev):
+async def test_invalid_connection(mocker: MockerFixture, dev: IotDevice) -> None:
     mocker.patch.object(FakeIotProtocol, "query", side_effect=KasaException)
     with pytest.raises(KasaException):
         await dev.update()
 
 
 @has_emeter_iot
-async def test_initial_update_emeter(dev, mocker):
+async def test_initial_update_emeter(dev: IotDevice, mocker: MockerFixture) -> None:
     """Test that the initial update performs second query if emeter is available."""
     dev._last_update = {}
     dev._legacy_features = set()
@@ -109,7 +110,7 @@ async def test_initial_update_emeter(dev, mocker):
 
 
 @no_emeter_iot
-async def test_initial_update_no_emeter(dev, mocker):
+async def test_initial_update_no_emeter(dev: IotDevice, mocker: MockerFixture) -> None:
     """Test that the initial update performs second query if emeter is available."""
     dev._last_update = {}
     dev._legacy_features = set()
@@ -128,7 +129,7 @@ async def test_initial_update_no_emeter(dev, mocker):
 
 
 @device_iot
-async def test_query_helper(dev):
+async def test_query_helper(dev: IotDevice) -> None:
     with pytest.raises(KasaException):
         await dev._query_helper("test", "testcmd", {})
     # TODO check for unwrapping?
@@ -136,7 +137,7 @@ async def test_query_helper(dev):
 
 @device_iot
 @turn_on
-async def test_state(dev, turn_on):
+async def test_state(dev: IotDevice, turn_on: bool) -> None:
     orig_state = dev.is_on
     await handle_turn_on(dev, turn_on)
     await dev.update()
@@ -164,7 +165,7 @@ async def test_state(dev, turn_on):
 
 @device_iot
 @turn_on
-async def test_on_since(dev, turn_on):
+async def test_on_since(dev: IotDevice, turn_on: bool) -> None:
     await handle_turn_on(dev, turn_on)
     orig_state = dev.is_on
     if "on_time" not in dev.sys_info and dev.device_type is not DeviceType.Strip:
@@ -176,43 +177,43 @@ async def test_on_since(dev, turn_on):
 
 
 @device_iot
-async def test_time(dev):
+async def test_time(dev: IotDevice) -> None:
     assert isinstance(dev.modules[Module.Time].time, datetime)
 
 
 @device_iot
-async def test_timezone(dev):
+async def test_timezone(dev: IotDevice) -> None:
     TZ_SCHEMA(await dev.modules[Module.Time].get_timezone())
 
 
 @device_iot
-async def test_hw_info(dev):
+async def test_hw_info(dev: IotDevice) -> None:
     SYSINFO_SCHEMA(dev.hw_info)
 
 
 @device_iot
-async def test_location(dev):
+async def test_location(dev: IotDevice) -> None:
     SYSINFO_SCHEMA(dev.location)
 
 
 @device_iot
-async def test_rssi(dev):
+async def test_rssi(dev: IotDevice) -> None:
     SYSINFO_SCHEMA({"rssi": dev.rssi})  # wrapping for vol
 
 
 @device_iot
-async def test_mac(dev):
+async def test_mac(dev: IotDevice) -> None:
     SYSINFO_SCHEMA({"mac": dev.mac})  # wrapping for val
 
 
 @device_iot
-async def test_representation(dev):
+async def test_representation(dev: IotDevice) -> None:
     pattern = re.compile(r"<DeviceType\..+ at .+? - .*? \(.+?\)>")
     assert pattern.match(str(dev))
 
 
 @device_iot
-async def test_children(dev):
+async def test_children(dev: IotDevice) -> None:
     """Make sure that children property is exposed by every device."""
     if dev.device_type is DeviceType.Strip:
         assert len(dev.children) > 0
@@ -221,7 +222,7 @@ async def test_children(dev):
 
 
 @device_iot
-async def test_modules_preserved(dev: IotDevice):
+async def test_modules_preserved(dev: IotDevice) -> None:
     """Make modules that are not being updated are preserved between updates."""
     dev._last_update["some_module_not_being_updated"] = "should_be_kept"
     await dev.update()
@@ -229,13 +230,13 @@ async def test_modules_preserved(dev: IotDevice):
 
 
 @device_iot
-async def test_internal_state(dev):
+async def test_internal_state(dev: IotDevice) -> None:
     """Make sure the internal state returns the last update results."""
     assert dev.internal_state == dev._last_update
 
 
 @device_iot
-async def test_features(dev):
+async def test_features(dev: IotDevice) -> None:
     """Make sure features is always accessible."""
     sysinfo = dev._last_update["system"]["get_sysinfo"]
     if "feature" in sysinfo:
@@ -245,20 +246,20 @@ async def test_features(dev):
 
 
 @device_iot
-async def test_max_device_response_size(dev):
+async def test_max_device_response_size(dev: IotDevice) -> None:
     """Make sure every device return has a set max response size."""
     assert dev.max_device_response_size > 0
 
 
 @device_iot
-async def test_estimated_response_sizes(dev):
+async def test_estimated_response_sizes(dev: IotDevice) -> None:
     """Make sure every module has an estimated response size set."""
     for mod in dev.modules.values():
         assert mod.estimated_query_response_size > 0
 
 
 @device_iot
-async def test_modules_not_supported(dev: IotDevice):
+async def test_modules_not_supported(dev: IotDevice) -> None:
     """Test that unsupported modules do not break the device."""
     for module in dev.modules.values():
         assert module.is_supported is not None
@@ -267,7 +268,7 @@ async def test_modules_not_supported(dev: IotDevice):
         assert module.is_supported is not None
 
 
-async def test_get_modules():
+async def test_get_modules() -> None:
     """Test getting modules for child and parent modules."""
     dummy_device = await get_device_for_fixture_protocol(
         "HS100(US)_2.0_1.5.6.json", "IOT"
@@ -293,10 +294,10 @@ async def test_get_modules():
     assert module is None
 
 
-def test_merge_dict():
+def test_merge_dict() -> None:
     """Test the recursive dict merge."""
-    dest = {"a": 1, "b": {"c": 2, "d": 3}}
-    source = {"b": {"c": 4, "e": 5}}
+    dest: dict = {"a": 1, "b": {"c": 2, "d": 3}}
+    source: dict = {"b": {"c": 4, "e": 5}}
     assert _merge_dict(dest, source) == {"a": 1, "b": {"c": 4, "d": 3, "e": 5}}
 
     dest = {"smartlife.iot.common.emeter": {"get_realtime": None}}
diff --git a/tests/iot/test_iotdimmer.py b/tests/iot/test_iotdimmer.py
index 38f440e70..561796d4a 100644
--- a/tests/iot/test_iotdimmer.py
+++ b/tests/iot/test_iotdimmer.py
@@ -1,4 +1,5 @@
 import pytest
+from pytest_mock import MockerFixture
 
 from kasa import DeviceType, Module
 from kasa.iot import IotDimmer
@@ -6,7 +7,7 @@
 
 
 @dimmer_iot
-async def test_set_brightness(dev):
+async def test_set_brightness(dev: IotDimmer) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     await handle_turn_on(dev, False)
@@ -26,7 +27,9 @@ async def test_set_brightness(dev):
 
 @dimmer_iot
 @turn_on
-async def test_set_brightness_transition(dev, turn_on, mocker):
+async def test_set_brightness_transition(
+    dev: IotDimmer, turn_on: bool, mocker: MockerFixture
+) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     await handle_turn_on(dev, turn_on)
@@ -49,7 +52,7 @@ async def test_set_brightness_transition(dev, turn_on, mocker):
 
 
 @dimmer_iot
-async def test_set_brightness_invalid(dev):
+async def test_set_brightness_invalid(dev: IotDimmer) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     for invalid_brightness in [-1, 101]:
@@ -62,7 +65,7 @@ async def test_set_brightness_invalid(dev):
 
 
 @dimmer_iot
-async def test_set_brightness_invalid_transition(dev):
+async def test_set_brightness_invalid_transition(dev: IotDimmer) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     for invalid_transition in [-1]:
@@ -74,7 +77,7 @@ async def test_set_brightness_invalid_transition(dev):
 
 
 @dimmer_iot
-async def test_turn_on_transition(dev, mocker):
+async def test_turn_on_transition(dev: IotDimmer, mocker: MockerFixture) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     query_helper = mocker.spy(IotDimmer, "_query_helper")
@@ -93,7 +96,7 @@ async def test_turn_on_transition(dev, mocker):
 
 
 @dimmer_iot
-async def test_turn_off_transition(dev, mocker):
+async def test_turn_off_transition(dev: IotDimmer, mocker: MockerFixture) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     await handle_turn_on(dev, True)
@@ -115,7 +118,9 @@ async def test_turn_off_transition(dev, mocker):
 
 @dimmer_iot
 @turn_on
-async def test_set_dimmer_transition(dev, turn_on, mocker):
+async def test_set_dimmer_transition(
+    dev: IotDimmer, turn_on: bool, mocker: MockerFixture
+) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     await handle_turn_on(dev, turn_on)
@@ -135,7 +140,9 @@ async def test_set_dimmer_transition(dev, turn_on, mocker):
 
 @dimmer_iot
 @turn_on
-async def test_set_dimmer_transition_to_off(dev, turn_on, mocker):
+async def test_set_dimmer_transition_to_off(
+    dev: IotDimmer, turn_on: bool, mocker: MockerFixture
+) -> None:
     light = dev.modules.get(Module.Light)
     assert light
     await handle_turn_on(dev, turn_on)
@@ -156,26 +163,26 @@ async def test_set_dimmer_transition_to_off(dev, turn_on, mocker):
 
 
 @dimmer_iot
-async def test_set_dimmer_transition_invalid_brightness(dev):
+async def test_set_dimmer_transition_invalid_brightness(dev: IotDimmer) -> None:
     for invalid_brightness in [-1, 101]:
         with pytest.raises(ValueError, match="Invalid brightness value: "):
             await dev.set_dimmer_transition(invalid_brightness, 1000)
 
     for invalid_type in [0.5, "foo"]:
         with pytest.raises(TypeError, match="Transition must be integer"):
-            await dev.set_dimmer_transition(1, invalid_type)
+            await dev.set_dimmer_transition(1, invalid_type)  # type: ignore[arg-type]
 
 
 @dimmer_iot
-async def test_set_dimmer_transition_invalid_transition(dev):
+async def test_set_dimmer_transition_invalid_transition(dev: IotDimmer) -> None:
     for invalid_transition in [-1]:
         with pytest.raises(ValueError, match="Transition value .+? is not valid."):
             await dev.set_dimmer_transition(1, transition=invalid_transition)
     for invalid_type in [0.5, "foo"]:
         with pytest.raises(TypeError, match="Transition must be integer"):
-            await dev.set_dimmer_transition(1, transition=invalid_type)
+            await dev.set_dimmer_transition(1, transition=invalid_type)  # type: ignore[arg-type]
 
 
 @dimmer_iot
-def test_device_type_dimmer(dev):
+def test_device_type_dimmer(dev: IotDimmer) -> None:
     assert dev.device_type == DeviceType.Dimmer
diff --git a/tests/iot/test_iotlightstrip.py b/tests/iot/test_iotlightstrip.py
index 23eb61dc9..c78780f82 100644
--- a/tests/iot/test_iotlightstrip.py
+++ b/tests/iot/test_iotlightstrip.py
@@ -1,4 +1,5 @@
 import pytest
+from pytest_mock import MockerFixture
 
 from kasa import DeviceType, Module
 from kasa.iot import IotLightStrip
@@ -7,13 +8,13 @@
 
 
 @lightstrip_iot
-async def test_lightstrip_length(dev: IotLightStrip):
+async def test_lightstrip_length(dev: IotLightStrip) -> None:
     assert dev.device_type == DeviceType.LightStrip
     assert dev.length == dev.sys_info["length"]
 
 
 @lightstrip_iot
-async def test_lightstrip_effect(dev: IotLightStrip):
+async def test_lightstrip_effect(dev: IotLightStrip) -> None:
     le: LightEffect = dev.modules[Module.LightEffect]
     assert isinstance(le._deprecated_effect, dict)
     for k in ["brightness", "custom", "enable", "id", "name"]:
@@ -21,7 +22,7 @@ async def test_lightstrip_effect(dev: IotLightStrip):
 
 
 @lightstrip_iot
-async def test_effects_lightstrip_set_effect(dev: IotLightStrip):
+async def test_effects_lightstrip_set_effect(dev: IotLightStrip) -> None:
     le: LightEffect = dev.modules[Module.LightEffect]
     with pytest.raises(
         ValueError, match="The effect Not real is not a built in effect"
@@ -36,8 +37,8 @@ async def test_effects_lightstrip_set_effect(dev: IotLightStrip):
 @lightstrip_iot
 @pytest.mark.parametrize("brightness", [100, 50])
 async def test_effects_lightstrip_set_effect_brightness(
-    dev: IotLightStrip, brightness, mocker
-):
+    dev: IotLightStrip, brightness: int, mocker: MockerFixture
+) -> None:
     query_helper = mocker.patch("kasa.iot.IotLightStrip._query_helper")
     le: LightEffect = dev.modules[Module.LightEffect]
 
@@ -55,8 +56,8 @@ async def test_effects_lightstrip_set_effect_brightness(
 @lightstrip_iot
 @pytest.mark.parametrize("transition", [500, 1000])
 async def test_effects_lightstrip_set_effect_transition(
-    dev: IotLightStrip, transition, mocker
-):
+    dev: IotLightStrip, transition: int, mocker: MockerFixture
+) -> None:
     query_helper = mocker.patch("kasa.iot.IotLightStrip._query_helper")
     le: LightEffect = dev.modules[Module.LightEffect]
 
@@ -72,12 +73,12 @@ async def test_effects_lightstrip_set_effect_transition(
 
 
 @lightstrip_iot
-async def test_effects_lightstrip_has_effects(dev: IotLightStrip):
+async def test_effects_lightstrip_has_effects(dev: IotLightStrip) -> None:
     le: LightEffect = dev.modules[Module.LightEffect]
     assert le is not None
     assert le.effect_list
 
 
 @lightstrip_iot
-def test_device_type_lightstrip(dev):
+def test_device_type_lightstrip(dev: IotLightStrip) -> None:
     assert dev.device_type == DeviceType.LightStrip
diff --git a/tests/iot/test_iotstrip.py b/tests/iot/test_iotstrip.py
index 50c1df618..1ef32c29a 100644
--- a/tests/iot/test_iotstrip.py
+++ b/tests/iot/test_iotstrip.py
@@ -1,11 +1,15 @@
 from unittest.mock import AsyncMock
 
+from pytest_mock import MockerFixture
+
 from kasa import Module
+from kasa.iot import IotStrip
+from kasa.iot.iotstrip import IotStripPlug
 from tests.conftest import strip_emeter_iot, strip_iot
 
 
 @strip_iot
-async def test_strip_update_and_child_update_behaviors(dev):
+async def test_strip_update_and_child_update_behaviors(dev: IotStrip) -> None:
     await dev.update()
     await dev.update(update_children=False)
 
@@ -18,9 +22,10 @@ async def test_strip_update_and_child_update_behaviors(dev):
 
 
 @strip_iot
-async def test_strip_child_delegated_properties(dev):
+async def test_strip_child_delegated_properties(dev: IotStrip) -> None:
     await dev.update()
     child = dev.children[0]
+    assert isinstance(child, IotStripPlug)
 
     assert child.led is False
     assert child.time == dev.time
@@ -32,7 +37,7 @@ async def test_strip_child_delegated_properties(dev):
 
 
 @strip_emeter_iot
-async def test_strip_emeter_erase_stats(dev, mocker):
+async def test_strip_emeter_erase_stats(dev: IotStrip, mocker: MockerFixture) -> None:
     await dev.update()
 
     for child in dev.children:
diff --git a/tests/iot/test_iottimezone.py b/tests/iot/test_iottimezone.py
index 640603b16..ae2f24f0d 100644
--- a/tests/iot/test_iottimezone.py
+++ b/tests/iot/test_iottimezone.py
@@ -5,7 +5,7 @@
 from pytest_mock import MockerFixture
 
 
-def test_expected_dst_behavior_for_index_cases():
+def test_expected_dst_behavior_for_index_cases() -> None:
     """Exercise _expected_dst_behavior_for_index for several representative indices."""
     from kasa.iot.iottimezone import _expected_dst_behavior_for_index
 
@@ -20,7 +20,7 @@ def test_expected_dst_behavior_for_index_cases():
         _expected_dst_behavior_for_index(999)
 
 
-async def test_guess_timezone_by_offset_fixed_fallback_unit():
+async def test_guess_timezone_by_offset_fixed_fallback_unit() -> None:
     """When no ZoneInfo matches, return a fixed-offset tzinfo."""
     import kasa.iot.iottimezone as tzmod
 
@@ -31,7 +31,7 @@ async def test_guess_timezone_by_offset_fixed_fallback_unit():
     assert tz.utcoffset(when) == offset
 
 
-async def test_guess_timezone_by_offset_candidates_unit():
+async def test_guess_timezone_by_offset_candidates_unit() -> None:
     """Cover naive when_utc branch and candidate selection path (non-empty candidates)."""
     import kasa.iot.iottimezone as tzmod
 
@@ -47,7 +47,7 @@ async def test_guess_timezone_by_offset_candidates_unit():
 
 async def test_guess_timezone_by_offset_dst_expected_true_filters(
     mocker: MockerFixture,
-):
+) -> None:
     """dst_expected=True should prefer a DST-observing zone when possible."""
     import kasa.iot.iottimezone as tzmod
 
@@ -62,7 +62,7 @@ async def test_guess_timezone_by_offset_dst_expected_true_filters(
         assert jan != jul  # observes DST
 
 
-async def test_guess_timezone_by_offset_dst_expected_false_prefers_non_dst():
+async def test_guess_timezone_by_offset_dst_expected_false_prefers_non_dst() -> None:
     """dst_expected=False should prefer a non-DST zone and skip DST candidates (covers False branch)."""
     import kasa.iot.iottimezone as tzmod
 
@@ -79,7 +79,7 @@ async def test_guess_timezone_by_offset_dst_expected_false_prefers_non_dst():
 
 async def test_guess_timezone_by_offset_handles_missing_zoneinfo_unit(
     mocker: MockerFixture,
-):
+) -> None:
     """Cover the ZoneInfoNotFoundError continue path within guess_timezone_by_offset."""
     from zoneinfo import ZoneInfoNotFoundError as ZNF
 
@@ -101,7 +101,7 @@ async def flaky_get(name: str):
     assert tz.utcoffset(when) == timedelta(0)
 
 
-async def test_get_timezone_index_direct_match():
+async def test_get_timezone_index_direct_match() -> None:
     """If ZoneInfo key is in TIMEZONE_INDEX, return index directly."""
     import kasa.iot.iottimezone as tzmod
 
@@ -109,7 +109,7 @@ async def test_get_timezone_index_direct_match():
     assert idx == 39  # "GB" is mapped to index 39
 
 
-async def test_get_timezone_index_non_zoneinfo_unit():
+async def test_get_timezone_index_non_zoneinfo_unit() -> None:
     """Exercise get_timezone_index path when input tzinfo is not a ZoneInfo instance."""
     import kasa.iot.iottimezone as tzmod
 
@@ -119,7 +119,7 @@ async def test_get_timezone_index_non_zoneinfo_unit():
     assert 0 <= idx <= 109
 
 
-async def test_get_timezone_index_skips_missing_unit(mocker: MockerFixture):
+async def test_get_timezone_index_skips_missing_unit(mocker: MockerFixture) -> None:
     """Cover ZoneInfoNotFoundError path in get_timezone_index loop and successful match."""
     from zoneinfo import ZoneInfoNotFoundError as ZNF
 
@@ -141,7 +141,7 @@ async def side_effect(i: int):
     assert idx >= 5
 
 
-async def test_get_timezone_index_raises_for_unmatched_unit():
+async def test_get_timezone_index_raises_for_unmatched_unit() -> None:
     """Ensure get_timezone_index completes loop and raises when no match exists (covers raise branch)."""
     import kasa.iot.iottimezone as tzmod
 
@@ -150,7 +150,7 @@ async def test_get_timezone_index_raises_for_unmatched_unit():
         await tzmod.get_timezone_index(timezone(timedelta(minutes=2)))
 
 
-async def test_get_matching_timezones_branches_unit(mocker: MockerFixture):
+async def test_get_matching_timezones_branches_unit(mocker: MockerFixture) -> None:
     """Cover initial append, except path, and duplicate suppression in get_matching_timezones."""
     from zoneinfo import ZoneInfoNotFoundError as ZNF
 
@@ -172,7 +172,7 @@ async def side_effect(i: int):
     # Loop should find GB again but not duplicate it
 
 
-async def test_get_matching_timezones_non_zoneinfo_unit():
+async def test_get_matching_timezones_non_zoneinfo_unit() -> None:
     """Exercise get_matching_timezones when input tzinfo is not a ZoneInfo (skips initial append)."""
     import kasa.iot.iottimezone as tzmod
 
@@ -181,7 +181,7 @@ async def test_get_matching_timezones_non_zoneinfo_unit():
     assert len(matches) > 0
 
 
-async def test_get_timezone_out_of_range_defaults_to_utc():
+async def test_get_timezone_out_of_range_defaults_to_utc() -> None:
     """Out-of-range index should log and default to UTC."""
     import kasa.iot.iottimezone as tzmod
 
diff --git a/tests/iot/test_wallswitch.py b/tests/iot/test_wallswitch.py
index b6fd2a673..3e2eac428 100644
--- a/tests/iot/test_wallswitch.py
+++ b/tests/iot/test_wallswitch.py
@@ -1,8 +1,10 @@
+from kasa.iot import IotWallSwitch
+
 from ..device_fixtures import wallswitch_iot
 
 
 @wallswitch_iot
-def test_wallswitch_motion(dev):
+def test_wallswitch_motion(dev: IotWallSwitch) -> None:
     """Check that wallswitches with motion sensor get modules enabled."""
     has_motion = "PIR" in dev.sys_info["dev_name"]
     assert "motion" in dev.modules if has_motion else True