Added coverage 314-349 and change in excel.py

Author: lsgordon

pandas/io/formats/excel.py

@@ -303,13 +303,13 @@ def _border_style(
         #       'slantDashDot'
         #       'thick'
         #       'thin'
-        if width is None and style is None and color is None:
-            # Return None will remove "border" from style dictionary
-            return None
-
         if width is None and style is None:
-            # Return "none" will keep "border" in style dictionary
-            return "none"
+            if color is None:
+                # Return None will remove "border" from style dictionary
+                return None
+            else:
+                # Return "none" will keep "border" in style dictionary
+                return "none"
 
         if style in ("none", "hidden"):
             return "none"

pandas/tests/io/formats/test_to_excel.py

@@ -155,6 +155,14 @@
         (
             "border-top-style: solid; border-top-width: 4pt",
             {"border": {"top": {"style": "thick"}}},
+        ),
+                (
+            "border-top-style: solid; border-top-width: none",
+            {"border": {"top": {"style": "none"}}},
+        ),
+        (
+            "border-top-style: solid; border-top-width: 0.000001pt",
+            {"border": {"top": {"style": "none"}}},
         ),
         (
             "border-top-style: dotted",
@@ -194,6 +202,12 @@
             "border-top-color: blue",
             {"border": {"top": {"color": "0000FF", "style": "none"}}},
         ),
+        (
+            "border-top-style: slantDashDot; border-top-color: blue",
+            {"border": {"top": {"style": "slantDashDot", "color": "0000FF"}}},
+        ),
+        
+        
         # ALIGNMENT
         # - horizontal
         ("text-align: center", {"alignment": {"horizontal": "center"}}),
@@ -249,6 +263,21 @@ def test_css_to_excel_multiple():
     } == actual
 
 
+@pytest.mark.parametrize(
+    "css",
+    [
+        "border-top-style: unhandled-border-style",
+        "border-style: another-unhandled-style",
+    ],
+)
+
+def test_css_to_excel_unhandled_border_style_warns(css):
+    """Test that unhandled border styles raise a CSSWarning."""
+    convert = CSSToExcelConverter()
+    with tm.assert_produces_warning(CSSWarning, match="Unhandled border style format"):
+        convert(css)
+
+
 @pytest.mark.parametrize(
     "css,inherited,expected",
     [