This. We kinda stumbled on this pattern, and use it to great effect. Simplified code:

@pytest.fixture
def tmpfiles():
    with NamedTemporaryFile(suffix=".html") as f:
        yield f

# or for paths, which are more suitable for certain tests
# touch them so they exist
@pytest.fixture
def othertmppaths() -> list[Path]:
    f1 = Path("...")
    f1.touch()
    f2 = Path("...")
    f2.touch()

    yield [f1, f2]
    # you could delete them here if needed
    f1.unlink()

def test_foo(othertmppaths list[Path]):
    result = upload_resource(othertmppaths[0]) 
    assert result.status == 200

The context manager one will properly clean up all files.

E: Pretty website btw