Merge pull request astropy#16925 from neutrinoceros/cosmology/rf/pth_…

…checks

MNT: Run PTH flake test in prep for supporting pathlib (cosmology)

.ruff.toml

@@ -220,7 +220,6 @@ lint.unfixable = [
     "RET505",  # superfluous-else-return
 ]
 "astropy/cosmology/*" = [
-    "PTH",     # all flake8-use-pathlib
     "C408",  # unnecessary-collection-call
     "PT019",   # pytest-fixture-param-without-value
 ]

astropy/cosmology/_io/tests/test_json.py

@@ -2,6 +2,7 @@
 
 import json
 import os
+from pathlib import Path
 
 import pytest
 
@@ -20,7 +21,7 @@ def read_json(filename, **kwargs):
 
     Parameters
     ----------
-    filename : str
+    filename : str | bytes | os.PathLike
     **kwargs
         Keyword arguments into :meth:`~astropy.cosmology.Cosmology.from_format`
 
@@ -30,8 +31,7 @@ def read_json(filename, **kwargs):
     """
     # read
     if isinstance(filename, (str, bytes, os.PathLike)):
-        with open(filename) as file:
-            data = file.read()
+        data = Path(filename).read_text()
     else:  # file-like : this also handles errors in dumping
         data = filename.read()
 
@@ -70,9 +70,10 @@ def write_json(cosmology, file, *, overwrite=False):
             data["meta"][k] = {"value": v.value.tolist(), "unit": str(v.unit)}
 
     # check that file exists and whether to overwrite.
-    if os.path.exists(file) and not overwrite:
+    file = Path(file)
+    if file.exists() and not overwrite:
         raise OSError(f"{file} exists. Set 'overwrite' to write over.")
-    with open(file, "w") as write_file:
+    with file.open("w") as write_file:
         json.dump(data, write_file)
 
 
@@ -125,8 +126,8 @@ def test_readwrite_json_subclass_partial_info(
         cosmo.write(fp, format="json")
 
         # partial information
-        with open(fp) as file:
-            L = file.readlines()[0]
+        with fp.open() as file:
+            L = file.readline()
         L = (
             L[: L.index('"cosmology":')] + L[L.index(", ") + 2 :]
         )  # remove cosmology  : #203
@@ -136,9 +137,7 @@ def test_readwrite_json_subclass_partial_info(
         )  # second occurrence  : #203
 
         tempfname = tmp_path / f"{cosmo.name}_temp.json"
-        with open(tempfname, "w") as file:
-            file.writelines([L])
-
+        tempfname.write_text("".join(L))
         # read with the same class that wrote fills in the missing info with
         # the default value
         got = cosmo_cls.read(tempfname, format="json")

astropy/cosmology/setup_package.py

@@ -1,11 +1,12 @@
 # Licensed under a 3-clause BSD style license - see LICENSE.rst
 
 import sys
-from os.path import dirname, join, relpath
+from os.path import relpath
+from pathlib import Path
 
 from setuptools import Extension
 
-ASTROPY_COSMOLOGY_ROOT = dirname(__file__)
+ASTROPY_COSMOLOGY_ROOT = Path(__file__).parent
 
 
 if sys.platform.startswith("win"):
@@ -22,7 +23,7 @@ def get_extensions():
     return [
         Extension(
             "astropy.cosmology._signature_deprecations",
-            [relpath(join(ASTROPY_COSMOLOGY_ROOT, "_signature_deprecations.c"))],
+            [relpath(Path(ASTROPY_COSMOLOGY_ROOT, "_signature_deprecations.c"))],
             extra_compile_args=extra_compile_args,
         ),
     ]

astropy/cosmology/tests/test_connect.py

@@ -1,7 +1,6 @@
 # Licensed under a 3-clause BSD style license - see LICENSE.rst
 
 import inspect
-import os
 
 import pytest
 
@@ -82,15 +81,15 @@ def test_readwrite_complete_info(self, cosmo, tmp_path, format, metaio, has_deps
         if (format, Cosmology) not in readwrite_registry._readers:
             pytest.xfail(f"no read method is registered for format {format!r}")
 
-        fname = str(tmp_path / f"{cosmo.name}.{format}")
+        fname = tmp_path / f"{cosmo.name}.{format}"
         cosmo.write(fname, format=format)
 
         # Also test kwarg "overwrite"
-        assert os.path.exists(fname)  # file exists
+        assert fname.is_file()
         with pytest.raises(IOError):
             cosmo.write(fname, format=format, overwrite=False)
 
-        assert os.path.exists(fname)  # overwrite file existing file
+        assert fname.exists()  # overwrite file existing file
         cosmo.write(fname, format=format, overwrite=True)
 
         # Read back