The default setting for master_doc is changed to 'index'

tests/test_build_html.py

@@ -249,7 +249,7 @@ def test_html_warnings(app, warning):
         # footnote reference
         (".//a[@class='footnote-reference']", r'\[1\]'),
         # created by reference lookup
-        (".//a[@href='contents.html#ref1']", ''),
+        (".//a[@href='index.html#ref1']", ''),
         # ``seealso`` directive
         (".//div/p[@class='first admonition-title']", 'See also'),
         # a ``hlist`` directive
@@ -348,7 +348,7 @@ def test_html_warnings(app, warning):
         (".//a[@class='reference internal'][@href='#cmdoption-git-commit-p']/code/span",
          '-p'),
     ],
-    'contents.html': [
+    'index.html': [
         (".//meta[@name='hc'][@content='hcval']", ''),
         (".//meta[@name='hc_co'][@content='hcval_co']", ''),
         (".//td[@class='label']", r'\[Ref1\]'),