Apply suggestions from code review

Co-authored-by: Eero Vaher <eero.vaher@gmail.com>

astropy/cosmology/io/ecsv.py

@@ -34,7 +34,7 @@ def read_ecsv(
         will be ``{'key': 10}``).
 
     rename : dict or None (optional keyword-only)
-        A dictionary mapping column names to fields of the Cosmology.
+        A dictionary mapping column names to fields of the `~astropy.cosmology.Cosmology`.
 
     **kwargs
         Passed to :attr:`astropy.table.QTable.read`
@@ -71,7 +71,7 @@ def write_ecsv(
 
     Parameters
     ----------
-    cosmology : |Cosmology|
+    cosmology : `~astropy.cosmology.Cosmology`
         The cosmology instance to convert to a mapping.
     file : path-like or file-like
         Location to save the serialized cosmology.
@@ -85,7 +85,7 @@ def write_ecsv(
         Whether to put the cosmology class in the Table metadata (if `True`,
         default) or as the first column (if `False`).
     rename : dict or None (optional keyword-only)
-        A dictionary mapping fields of the Cosmology to columns of the table.
+        A dictionary mapping fields of the `~astropy.cosmology.Cosmology` to columns of the table.
 
     **kwargs
         Passed to ``cls.write``

astropy/cosmology/io/mapping.py

@@ -66,7 +66,8 @@ class itself.
         filling in any non-mandatory arguments missing in 'map'.
 
     rename : dict or None (optional, keyword-only)
-        A dictionary mapping keys in 'map' to fields of the Cosmology.
+        A dictionary mapping keys in ``map`` to fields of the
+        `~astropy.cosmology.Cosmology`.
 
     Returns
     -------

astropy/cosmology/io/row.py

@@ -11,7 +11,7 @@
 
 
 def from_row(row, *, move_to_meta=False, cosmology=None, rename=None):
-    """Instantiate a |Cosmology| from a `~astropy.table.Row`.
+    """Instantiate a `~astropy.cosmology.Cosmology` from a `~astropy.table.Row`.
 
     Parameters
     ----------
@@ -32,11 +32,11 @@ def from_row(row, *, move_to_meta=False, cosmology=None, rename=None):
         filling in any non-mandatory arguments missing in 'table'.
 
     rename : dict or None (optional, keyword-only)
-        A dictionary mapping columns in the row to fields of the Cosmology.
+        A dictionary mapping columns in the row to fields of the `~astropy.cosmology.Cosmology`.
 
     Returns
     -------
-    |Cosmology| subclass instance
+    `~astropy.cosmology.Cosmology`
 
     Examples
     --------
@@ -68,7 +68,7 @@ def from_row(row, *, move_to_meta=False, cosmology=None, rename=None):
     kcosmo = inv_rename.get("cosmology", "cosmology")
 
     # special values
-    name = row[kname] if kname in row.columns else None  # get name from column
+    name = row.get(kname)
 
     meta = defaultdict(dict, copy.deepcopy(row.meta))
     # Now need to add the Columnar metadata. This is only available on the
@@ -95,7 +95,7 @@ def to_row(cosmology, *args, cosmology_in_meta=False, table_cls=QTable, rename=N
 
     Parameters
     ----------
-    cosmology : |Cosmology|
+    cosmology : `~astropy.cosmology.Cosmology`
         The cosmology instance to convert to a mapping.
     *args
         Not used. Needed for compatibility with
@@ -116,7 +116,7 @@ def to_row(cosmology, *args, cosmology_in_meta=False, table_cls=QTable, rename=N
 
     Examples
     --------
-    A Cosmology as a `~astropy.table.Row` will have the cosmology's name and parameters
+    A `~astropy.cosmology.Cosmology` as a `~astropy.table.Row` will have the cosmology's name and parameters
     as columns.
 
         >>> from astropy.cosmology import Planck18

astropy/cosmology/io/table.py

@@ -33,17 +33,17 @@ def from_table(table, index=None, *, move_to_meta=False, cosmology=None, rename=
         (e.g. for ``Cosmology(meta={'key':10}, key=42)``, the ``Cosmology.meta``
         will be ``{'key': 10}``).
 
-    cosmology : str or |Cosmology| class or None (optional, keyword-only)
+    cosmology : str or type or None (optional, keyword-only)
         The cosmology class (or string name thereof) to use when constructing
         the cosmology instance. The class also provides default parameter values,
         filling in any non-mandatory arguments missing in 'table'.
 
     rename : dict or None (optional, keyword-only)
-        A dictionary mapping columns in 'table' to fields of the Cosmology class.
+        A dictionary mapping columns in 'table' to fields of the `~astropy.cosmology.Cosmology` class.
 
     Returns
     -------
-    |Cosmology| subclass instance
+    `~astropy.cosmology.Cosmology`
 
     Examples
     --------
@@ -115,7 +115,10 @@ def from_table(table, index=None, *, move_to_meta=False, cosmology=None, rename=
         if not table.indices:  # no indexing column, find by string match
             nc = "name"  # default name column
             if rename is not None:  # from inverted `rename`
-                nc = {v: k for k, v in rename.items()}.get(nc, nc)
+                for key, value in rename.items():
+                    if value == "name":
+                        nc = key
+                        break
 
             indices = np.where(table[nc] == index)[0]
         else:  # has indexing column
@@ -150,7 +153,7 @@ def to_table(cosmology, *args, cls=QTable, cosmology_in_meta=True, rename=None):
 
     Parameters
     ----------
-    cosmology : |Cosmology| subclass instance
+    cosmology : `~astropy.cosmology.Cosmology`
         The cosmology instance to convert to a table.
     *args
         Not used. Needed for compatibility with
@@ -242,7 +245,7 @@ def to_table(cosmology, *args, cls=QTable, cosmology_in_meta=True, rename=None):
     tbl = cls(data, meta=meta)
 
     # Renames
-    renames = {} if rename is None else rename
+    renames = rename or {}
     for name in tbl.colnames:
         tbl.rename_column(name, renames.get(name, name))
 

astropy/cosmology/io/tests/test_ecsv.py

@@ -127,7 +127,7 @@ def test_readwrite_ecsv_instance(
         got = read(fp)
         assert got == cosmo
 
-    def test_readwrite_ecsv_rename(
+    def test_readwrite_ecsv_renamed_columns(
         self, cosmo_cls, cosmo, read, write, tmp_path, add_cu
     ):
         """Test rename argument to read/write."""

astropy/cosmology/io/tests/test_mapping.py

@@ -135,7 +135,7 @@ def test_to_mapping_rename_conflict(self, cosmo, to_format):
         with pytest.raises(ValueError, match="'renames' values must be disjoint"):
             to_format("mapping", rename=to_rename)
 
-    def test_from_mapping_rename_disjoint(self, cosmo, to_format, from_format):
+    def test_from_mapping_rename_conflict(self, cosmo, to_format, from_format):
         """Test ``rename`` in `from_mapping()``."""
         m = to_format("mapping")