diff --git a/tests/test_tables.py b/tests/test_tables.py
index 453e4ca8..c866bdc0 100644
--- a/tests/test_tables.py
+++ b/tests/test_tables.py
@@ -1996,6 +1996,12 @@ def test_num_columns(table):
     number = table.num_columns
     assert number == 3
 
+def test_as_label(table):
+    """Test that as_label raises ValueError for invalid index_or_label along with correct message"""
+    
+    with pytest.raises(ValueError) as t:
+        table.set_format(None, CurrencyFormatter(int_to_float=True))
+    assert str(t.value) == "None is not a label or index"
 def test_split(table):
     """Test that split copies over the _formats variable from the original table to the new tables correctly after splitting"""