Fix tests for pueblo.ngr

Not all packages are installed on those test jobs.

tests/test_dataframe.py

@@ -1,6 +1,9 @@
+# ruff: noqa: E402
 from pathlib import Path
 
-import pandas as pd
+import pytest
+
+pd = pytest.importorskip("pandas")
 from dask.utils import is_dataframe_like
 from pandas._testing import raise_assert_detail
 

tests/test_io.py

@@ -2,9 +2,10 @@
 import dataclasses
 import typing as t
 
-import magic
 import pytest
 
+magic = pytest.importorskip("magic")
+
 pytest.importorskip("pathlibfs")
 from pathlibfs import Path as PathPlus
 

tests/test_proc.py

@@ -1,6 +1,7 @@
 import pytest
 
-from pueblo.util.proc import process
+proc = pytest.importorskip("pueblo.util.proc")
+process = proc.process
 
 
 def test_process_success(tmp_path):