Fix stale auto-mode comment and harden GS-raises test

src/ocrmypdf/_pipelines/_common.py

@@ -489,7 +489,7 @@ def postprocess(
         else:
             pdf_out = pdf_file
     if context.options.output_type == 'auto':
-        # Best effort PDF/A - never uses Ghostscript
+        # Best effort PDF/A - may use Ghostscript as a last resort
         pdf_out, actual_type = try_auto_pdfa(pdf_out, context)
         # Store actual output type for reporting
         context.options.extra_attrs['_actual_output_type'] = actual_type

tests/test_pdfa.py

@@ -205,6 +205,7 @@ def test_auto_degrades_when_ghostscript_raises(resources, outpdf, monkeypatch):
     from ocrmypdf.exceptions import ColorConversionNeededError
 
     monkeypatch.setattr('ocrmypdf._exec.verapdf.available', lambda: False)
+    monkeypatch.setattr('ocrmypdf._exec.ghostscript.available', lambda: True)
 
     def boom(*args, **kwargs):
         raise ColorConversionNeededError()
@@ -219,6 +220,7 @@ def test_auto_degrades_when_ghostscript_raises(resources, outpdf, monkeypatch):
         'auto',
     )
     assert exitcode == ExitCode.ok
+    assert outpdf.exists()
     assert not file_claims_pdfa(outpdf)['pass']