diff --git a/src/ocrmypdf/api.py b/src/ocrmypdf/api.py
index b735f398..a05edbc1 100644
--- a/src/ocrmypdf/api.py
+++ b/src/ocrmypdf/api.py
@@ -158,7 +158,7 @@ def create_options(*, input_file, output_file, **kwargs):
 
     # If we are running a Tesseract spoof, ensure it knows what the input file is
     if os.environ.get('PYTEST_CURRENT_TEST') and options.tesseract_env:
-        options.tesseract_env['_OCRMYPDF_TEST_INFILE'] = input_file
+        options.tesseract_env['_OCRMYPDF_TEST_INFILE'] = os.fspath(input_file)
 
     return options
 
diff --git a/tests/conftest.py b/tests/conftest.py
index b443ac1f..e875315a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -183,7 +183,7 @@ def check_ocrmypdf(input_file, output_file, *args, env=None):
     api.check_options(options)
     if env:
         options.tesseract_env = env
-        options.tesseract_env['_OCRMYPDF_TEST_INFILE'] = input_file
+        options.tesseract_env['_OCRMYPDF_TEST_INFILE'] = os.fspath(input_file)
     result = api.run_pipeline(options, api=True)
 
     assert result == 0