Ensure specified position is >= 1

enlighten/_manager.py

@@ -240,15 +240,19 @@ def _add_counter(self, counter_class, *args, **kwargs):  # pylint: disable=too-m
                 new._pinned = True
                 pinned[position] = new
 
-        # Check position
+        # Position specified
         elif position is not None:
+            if position < 1:
+                raise ValueError('Counter position %d is less than 1.' % position)
             if position in pinned:
                 raise ValueError('Counter position %d is already occupied.' % position)
             if position > self.height:
                 raise ValueError('Counter position %d is greater than terminal height.' % position)
             new._pinned = True  # pylint: disable=protected-access
             self.counters[new] = position
             pinned[position] = new
+
+        # Dynamic placement
         else:
             # Set for now, but will change
             self.counters[new] = 0

tests/test_manager.py

@@ -186,6 +186,9 @@ def test_counter_position(self):
         counter1 = manager.counter(position=4)
         self.assertEqual(manager.counters[counter1], 4)
 
+        with self.assertRaisesRegex(ValueError, 'Counter position 0 is less than 1'):
+            manager.counter(position=0)
+
         with self.assertRaisesRegex(ValueError, 'Counter position 4 is already occupied'):
             manager.counter(position=4)