Fix rangefilter (#17473)

* Fix rangefilter

RangeFilter would break for lower or upper bounds of 0, evaluating to False and thus not being handled correctly as bounds

* Add test for zero bounds

homeassistant/components/sensor/filter.py

@@ -347,7 +347,7 @@ class RangeFilter(Filter):
     """
 
     def __init__(self, entity,
-                 lower_bound, upper_bound):
+                 lower_bound=None, upper_bound=None):
         """Initialize Filter."""
         super().__init__(FILTER_NAME_RANGE, entity=entity)
         self._lower_bound = lower_bound
@@ -356,7 +356,8 @@ class RangeFilter(Filter):
 
     def _filter_state(self, new_state):
         """Implement the range filter."""
-        if self._upper_bound and new_state.state > self._upper_bound:
+        if (self._upper_bound is not None
+                and new_state.state > self._upper_bound):
 
             self._stats_internal['erasures_up'] += 1
 
@@ -365,7 +366,8 @@ class RangeFilter(Filter):
                           self._entity, new_state)
             new_state.state = self._upper_bound
 
-        elif self._lower_bound and new_state.state < self._lower_bound:
+        elif (self._lower_bound is not None
+              and new_state.state < self._lower_bound):
 
             self._stats_internal['erasures_low'] += 1
 

tests/components/sensor/test_filter.py

@@ -149,6 +149,23 @@ class TestFilterSensor(unittest.TestCase):
             else:
                 self.assertEqual(unf, filtered.state)
 
+    def test_range_zero(self):
+        """Test if range filter works with zeroes as bounds."""
+        lower = 0
+        upper = 0
+        filt = RangeFilter(entity=None,
+                           lower_bound=lower,
+                           upper_bound=upper)
+        for unf_state in self.values:
+            unf = float(unf_state.state)
+            filtered = filt.filter_state(unf_state)
+            if unf < lower:
+                self.assertEqual(lower, filtered.state)
+            elif unf > upper:
+                self.assertEqual(upper, filtered.state)
+            else:
+                self.assertEqual(unf, filtered.state)
+
     def test_throttle(self):
         """Test if lowpass filter works."""
         filt = ThrottleFilter(window_size=3,