Do not replace unicode characters by LaTeX macros on unicode supported LaTeX engines

tests/test_build_latex.py

@@ -1437,3 +1437,27 @@ def test_index_on_title(app, status, warning):
             '\\label{\\detokenize{contents:test-for-index-in-top-level-title}}'
             '\\index{index@\\spxentry{index}}\n'
             in result)
+
+
+@pytest.mark.sphinx('latex', testroot='latex-unicode',
+                    confoverrides={'latex_engine': 'pdflatex'})
+def test_texescape_for_non_unicode_supported_engine(app, status, warning):
+    app.builder.build_all()
+    result = (app.outdir / 'python.tex').text()
+    print(result)
+    assert 'script small e: e' in result
+    assert 'double struck italic small i: i' in result
+    assert r'superscript: \(\sp{\text{0}}\), \(\sp{\text{1}}\)' in result
+    assert r'subscript: \(\sb{\text{0}}\), \(\sb{\text{1}}\)' in result
+
+
+@pytest.mark.sphinx('latex', testroot='latex-unicode',
+                    confoverrides={'latex_engine': 'xelatex'})
+def test_texescape_for_unicode_supported_engine(app, status, warning):
+    app.builder.build_all()
+    result = (app.outdir / 'python.tex').text()
+    print(result)
+    assert 'script small e: e' in result
+    assert 'double struck italic small i: i' in result
+    assert 'superscript: ⁰, ¹' in result
+    assert 'subscript: ₀, ₁' in result