Separate testcase for html_style to single case from root

tests/roots/test-html_style/conf.py

@@ -0,0 +1,2 @@
+html_style = 'default.css'
+html_static_path = ['_static']

tests/roots/test-html_style/contents.rst

@@ -0,0 +1,2 @@
+html_style
+==========

tests/roots/test-root/conf.py

@@ -39,7 +39,6 @@ html_sidebars = {'**': ['localtoc.html', 'relations.html', 'sourcelink.html',
                         'customsb.html', 'searchbox.html'],
                  'contents': ['contentssb.html', 'localtoc.html',
                               'globaltoc.html']}
-html_style = 'default.css'
 html_last_updated_fmt = '%b %d, %Y'
 html_context = {'hckey': 'hcval', 'hckey_co': 'wrong_hcval_co'}
 

tests/test_build_html.py

@@ -1258,6 +1258,15 @@ def test_alternate_stylesheets(app, cached_etree_parse, fname, expect):
     check_xpath(cached_etree_parse(app.outdir / fname), fname, *expect)
 
 
+@pytest.mark.sphinx('html', testroot='html_style')
+def test_html_style(app, status, warning):
+    app.build()
+    result = (app.outdir / 'contents.html').text()
+    assert '<link rel="stylesheet" href="_static/default.css" type="text/css" />' in result
+    assert ('<link rel="stylesheet" href="_static/alabaster.css" type="text/css" />'
+            not in result)
+
+
 @pytest.mark.sphinx('html', testroot='images')
 def test_html_remote_images(app, status, warning):
     app.builder.build_all()