diff --git a/make_index.py b/make_index.py
index a8bdb461..61c71d62 100644
--- a/make_index.py
+++ b/make_index.py
@@ -118,7 +118,7 @@ def main(argv: Sequence[str] | None = None) -> int:
             (
                 sys.executable,
                 "-mdumb_pypi.main",
-                # f"--previous-package-list-json={prev_json}",
+                f"--previous-package-list-json={prev_json}",
                 f"--package-list-json={packages_json}",
                 f"--output-dir={args.dest}",
                 f'--packages-url={urllib.parse.urljoin(args.pypi_url, "wheels")}',
diff --git a/tests/make_index_test.py b/tests/make_index_test.py
index 8bd8f8c7..48a9570f 100644
--- a/tests/make_index_test.py
+++ b/tests/make_index_test.py
@@ -8,7 +8,6 @@
 import zipfile
 from unittest import mock
 
-import pytest
 import re_assert
 
 import make_index
@@ -144,7 +143,6 @@ def test_main_multiple_provide_same_package_first_wins(tmp_path):
     assert contents["requires_python"] == ">=3"
 
 
-@pytest.mark.skip
 def test_main_previous_packages_exist(tmp_path):
     dist = tmp_path.joinpath("dist")
     dist.mkdir()