Makes sure YAML defined tariffs are unique (#69151)

homeassistant/components/utility_meter/__init__.py

@@ -85,7 +85,7 @@ METER_CONFIG_SCHEMA = vol.Schema(
             vol.Optional(CONF_METER_DELTA_VALUES, default=False): cv.boolean,
             vol.Optional(CONF_METER_NET_CONSUMPTION, default=False): cv.boolean,
             vol.Optional(CONF_TARIFFS, default=[]): vol.All(
-                cv.ensure_list, [cv.string]
+                cv.ensure_list, vol.Unique(), [cv.string]
             ),
             vol.Optional(CONF_CRON_PATTERN): validate_cron_pattern,
         },

tests/components/utility_meter/test_sensor.py

@@ -226,6 +226,27 @@ async def test_state(hass, yaml_config, config_entry_config):
     assert state.state == "0.123"
 
 
+@pytest.mark.parametrize(
+    "yaml_config",
+    (
+        (
+            {
+                "utility_meter": {
+                    "energy_bill": {
+                        "source": "sensor.energy",
+                        "tariffs": ["onpeak", "onpeak"],
+                    }
+                }
+            },
+            None,
+        ),
+    ),
+)
+async def test_not_unique_tariffs(hass, yaml_config):
+    """Test utility sensor state initializtion."""
+    assert not await async_setup_component(hass, DOMAIN, yaml_config)
+
+
 @pytest.mark.parametrize(
     "yaml_config,config_entry_config",
     (