Numeric state trigger: validate that above is not above below (#32421)

* Numeric state trigger: validate that above is not above below

* Lint

homeassistant/components/automation/numeric_state.py

@@ -19,6 +19,23 @@ from homeassistant.helpers.event import async_track_same_state, async_track_stat
 # mypy: allow-incomplete-defs, allow-untyped-calls, allow-untyped-defs
 # mypy: no-check-untyped-defs
 
+
+def validate_above_below(value):
+    """Validate that above and below can co-exist."""
+    above = value.get(CONF_ABOVE)
+    below = value.get(CONF_BELOW)
+
+    if above is None or below is None:
+        return value
+
+    if above > below:
+        raise vol.Invalid(
+            f"A value can never be above {above} and below {below} at the same time. You probably want two different triggers.",
+        )
+
+    return value
+
+
 TRIGGER_SCHEMA = vol.All(
     vol.Schema(
         {
@@ -35,6 +52,7 @@ TRIGGER_SCHEMA = vol.All(
         }
     ),
     cv.has_at_least_one_key(CONF_BELOW, CONF_ABOVE),
+    validate_above_below,
 )
 
 _LOGGER = logging.getLogger(__name__)