diff --git a/tests/test_build_latex.py b/tests/test_build_latex.py
index 58eaf90f8..f02394cf1 100644
--- a/tests/test_build_latex.py
+++ b/tests/test_build_latex.py
@@ -1414,7 +1414,7 @@ def test_includegraphics_oversized(app, status, warning):
 @pytest.mark.sphinx('latex', testroot='index_on_title')
 def test_index_on_title(app, status, warning):
     app.builder.build_all()
-    result = (app.outdir / 'Python.tex').text(encoding='utf8')
+    result = (app.outdir / 'python.tex').text(encoding='utf8')
     assert ('\\chapter{Test for index in top level title}\n'
             '\\label{\\detokenize{contents:test-for-index-in-top-level-title}}'
             '\\index{index@\\spxentry{index}}\n'