Adding further coverage for excel.py

Author: lsgordon

pandas/io/formats/excel.py

@@ -411,11 +411,6 @@ def _get_decoration(self, props: Mapping[str, str]) -> Sequence[str]:
         else:
             return ()
 
-    def _get_underline(self, decoration: Sequence[str]) -> str | None:
-        if "underline" in decoration:
-            return "single"
-        return None
-
     def _get_shadow(self, props: Mapping[str, str]) -> bool | None:
         if "text-shadow" in props:
             return bool(re.search("^[^#(]*[1-9]", props["text-shadow"]))

pandas/tests/io/formats/test_to_excel.py

@@ -358,6 +358,21 @@ def test_css_to_excel_bad_colors(input_color):
         convert = CSSToExcelConverter()
         assert expected == convert(css)
 
+@pytest.mark.parametrize("input_color", ["#", "#1234567"])
+def test_css_to_excel_invalid_color_raises(input_color):
+    """Test that invalid colors raise a ValueError."""
+    css = (
+        f"border-top-color: {input_color}; "
+        f"border-right-color: {input_color}; "
+        f"border-bottom-color: {input_color}; "
+        f"border-left-color: {input_color}; "
+        f"background-color: {input_color}; "
+        f"color: {input_color}"
+    )
+
+    convert = CSSToExcelConverter()
+    with pytest.raises(ValueError, match=f"Unexpected color {input_color}"):
+        convert(css)
 
 def tests_css_named_colors_valid():
     upper_hexs = set(map(str.upper, string.hexdigits))