add tests, remove conflicting args input

pandas-dev · attack68 · Dec 24, 2021 · Dec 24, 2021 · Dec 24, 2021 · Dec 24, 2021
commit 143f629f0557b266af5ab5489018133ce17deafc
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
@@ -3299,21 +3299,6 @@ def _to_html_via_styler(
 
         if header is False:
             styler.hide(axis=1)
-        elif isinstance(header, list):
-            # use styler format to output the column name aliases
-            if len(header) != len(styler.columns):
-                raise ValueError(
-                    f"`header` gave {len(header)} aliases for {len(styler.columns)} "
-                    f"columns."
-                )
-
-            def disp(x, v):  # use partial to create a distinct, in loop runtime func
-                return f"{v}"
-
-            for i, val in enumerate(header):
-                styler._display_funcs_columns[(0, i)] = functools.partial(disp, v=val)
-            if isinstance(styler.columns, MultiIndex):
-                styler.hide(axis=1, level=list(range(1, styler.columns.nlevels)))
         if not index:
             styler.hide(axis=0)
         if index_names is False or index_names in ["none", "columns"]:

diff --git a/pandas/tests/io/formats/test_to_html.py b/pandas/tests/io/formats/test_to_html.py
@@ -888,3 +888,41 @@ def test_to_html_float_format_object_col(datapath):
     result = df.to_html(float_format=lambda x: f"{x:,.0f}")
     expected = expected_html(datapath, "gh40024_expected_output")
     assert result == expected
+
+
+#####
+# Tests for Styler Implementation of DataFrame.to_html:
+# styler implementation has its own tests.
+# these test only the parsing of the kwargs to df.to_html and the appropriate action.
+#####
+
+
+@pytest.mark.parametrize("header", [True])
+@pytest.mark.parametrize("index_names", [True])
+@pytest.mark.parametrize("index", [True])
+def test_to_html_styler_header(header, index_names, index):
+    df = DataFrame([[1]], index=["I"], columns=["C"])
+    df.columns.name, df.index.name = "Cname", "Iname"
+    result = df.to_html(
+        caption="styler_implementation",
+        index=index,
+        header=header,
+        index_names=index_names,
+    )
+
+    assert ("<th >Cname</th>" in result) is index_names
+    assert ("<th >Iname</th>" in result) is index_names
+    assert ("<th >C</th>" in result) is header
+    assert ("<th >I</th>" in result) is index
+
+    # check that the styler implementation was called..
+    assert result != df.to_html(index=index, header=header, index_name=index_names)
+
+
+def test_to_html_styler_columns_header():
+    df_base = DataFrame([[1]], index=["I"], columns=["C"])
+    df = DataFrame([[1, 1]], index=["I"], columns=["C", "D"])
+
+    # test column subset is applied
+    result = df.to_html(caption="styler_implementation", columns=["C"])
+    assert result == df_base.to_html(caption="styler_implementation")