consolidate representers and test

src/uwtools/config/formats/yaml.py

@@ -1,19 +1,11 @@
-from collections import OrderedDict
 from pathlib import Path
 from types import SimpleNamespace as ns
 from typing import Optional
 
 import yaml
-from f90nml import Namelist  # type: ignore
 
 from uwtools.config.formats.base import Config
-from uwtools.config.support import (
-    INCLUDE_TAG,
-    TaggedString,
-    log_and_error,
-    represent_namelist,
-    represent_ordereddict,
-)
+from uwtools.config.support import INCLUDE_TAG, TaggedString, add_representers, log_and_error
 from uwtools.utils.file import FORMAT, readable, writable
 
 _MSGS = ns(
@@ -52,9 +44,7 @@ def __repr__(self) -> str:
         """
         The string representation of a YAMLConfig object.
         """
-        yaml.add_representer(TaggedString, TaggedString.represent)
-        yaml.add_representer(Namelist, represent_namelist)
-        yaml.add_representer(OrderedDict, represent_ordereddict)
+        add_representers()
         return yaml.dump(self.data, default_flow_style=False).strip()
 
     # Private methods
@@ -125,9 +115,7 @@ def dump_dict(cfg: dict, path: Optional[Path] = None) -> None:
         :param cfg: The in-memory config object to dump.
         :param path: Path to dump config to.
         """
-        yaml.add_representer(TaggedString, TaggedString.represent)
-        yaml.add_representer(Namelist, represent_namelist)
-        yaml.add_representer(OrderedDict, represent_ordereddict)
+        add_representers()
         with writable(path) as f:
             yaml.dump(cfg, f, sort_keys=False)
 

src/uwtools/config/support.py

@@ -14,6 +14,20 @@
 INCLUDE_TAG = "!INCLUDE"
 
 
+# Public functions
+def add_representers():
+    """
+    Add representers to the YAML dumper for custom types.
+
+    This function is called by the YAMLConfig class to add representers for the TaggedString,
+    Namelist, and OrderedDict types to the YAML dumper. The representers are used to serialize these
+    types to YAML.
+    """
+    yaml.add_representer(TaggedString, TaggedString.represent)
+    yaml.add_representer(Namelist, _represent_namelist)
+    yaml.add_representer(OrderedDict, _represent_ordereddict)
+
+
 def depth(d: dict) -> int:
     """
     The depth of a dictionary.
@@ -55,7 +69,7 @@ def log_and_error(msg: str) -> Exception:
     return UWConfigError(msg)
 
 
-def represent_namelist(dumper: yaml.Dumper, data: Namelist) -> yaml.nodes.MappingNode:
+def _represent_namelist(dumper: yaml.Dumper, data: Namelist) -> yaml.nodes.MappingNode:
     """
     Convert f90nml Namelist to OrderedDict and serialize.
 
@@ -69,7 +83,7 @@ def represent_namelist(dumper: yaml.Dumper, data: Namelist) -> yaml.nodes.Mappin
     return dumper.represent_mapping("tag:yaml.org,2002:map", namelist_dict)
 
 
-def represent_ordereddict(dumper: yaml.Dumper, data: OrderedDict) -> yaml.nodes.MappingNode:
+def _represent_ordereddict(dumper: yaml.Dumper, data: OrderedDict) -> yaml.nodes.MappingNode:
     """
     Convert OrderedDict to dict and serialize.
 

src/uwtools/tests/config/test_support.py

@@ -8,7 +8,7 @@
 
 import pytest
 import yaml
-from f90nml import reads  # type: ignore
+from f90nml import Namelist, reads  # type: ignore
 from pytest import fixture, raises
 
 from uwtools.config import support
@@ -23,6 +23,14 @@
 from uwtools.utils.file import FORMAT
 
 
+def test_add_representers():
+    support.add_representers()
+    representers = yaml.Dumper.yaml_representers
+    assert support.TaggedString in representers
+    assert OrderedDict in representers
+    assert Namelist in representers
+
+
 @pytest.mark.parametrize(
     "d,n", [({1: 88}, 1), ({1: {2: 88}}, 2), ({1: {2: {3: 88}}}, 3), ({1: {}}, 2)]
 )