add test for "attr:;", ie empty value

Author: invalidarg

pandas/tests/io/formats/style/test_style.py

@@ -889,6 +889,10 @@ def test_maybe_convert_css_to_tuples(self):
         #issue #59623
         expected = [("a", "b"), ("c", "url('data:123')")]
         assert maybe_convert_css_to_tuples("a:b;c: url('data:123');") == expected
+
+        #if no value, return attr and empty string
+        expected = [("a", ""), ("c", "")]
+        assert maybe_convert_css_to_tuples("a:;c: ") == expected
 
 
     def test_maybe_convert_css_to_tuples_err(self):