Improve NeighborList tests.

qutebrowser/utils/usertypes.py

@@ -147,7 +147,7 @@ class NeighborList(collections.abc.Sequence):
                 self._idx += offset
                 self._idx %= len(self.items)
                 new = self.curitem()
-            elif self._mode == self.Modes.exception:
+            elif self._mode == self.Modes.exception:  # pragma: no branch
                 raise
         else:
             self._idx += offset

tests/utils/usertypes/test_neighborlist.py

@@ -51,6 +51,11 @@ class TestInit:
         assert 2 in nl
         assert 4 not in nl
 
+    def test_invalid_mode(self):
+        """Test with an invalid mode."""
+        with pytest.raises(TypeError):
+            usertypes.NeighborList(mode='blah')
+
 
 class TestDefaultArg:
 
@@ -71,6 +76,12 @@ class TestDefaultArg:
         nl = usertypes.NeighborList([1, 2, 3])
         assert nl._idx is None
 
+    def test_invalid_reset(self):
+        """Test reset without default."""
+        nl = usertypes.NeighborList([1, 2, 3, 4, 5])
+        with pytest.raises(ValueError):
+            nl.reset()
+
 
 class TestEmpty: