Update lib/matplotlib/tests/test_sphinxext.py

Co-authored-by: Elliott Sales de Andrade <[email protected]>

Author: harupy

lib/matplotlib/tests/test_sphinxext.py

@@ -123,7 +123,7 @@ def build_sphinx_html(source_dir, doctree_dir, html_dir, extra_args=None):
     # Build the pages with warnings turned into errors
     extra_args = [] if extra_args is None else extra_args
     cmd = [sys.executable, '-msphinx', '-W', '-b', 'html',
-           '-d', str(doctree_dir), str(source_dir), str(html_dir)] + extra_args
+           '-d', str(doctree_dir), str(source_dir), str(html_dir), *extra_args]
     proc = Popen(cmd, stdout=PIPE, stderr=PIPE, universal_newlines=True,
                  env={**os.environ, "MPLBACKEND": ""})
     out, err = proc.communicate()