feat(plexos): plexos parser xml (#93)

Update the plexos parser to find a single xml file in the run_directory
when available. If the fmap is provided that will be used in favor of
finding the only xml file. When multiple xml files are present, this
will raise an Error, and then the fmap will be required again.

src/r2x/parser/plexos.py

@@ -56,6 +56,7 @@
     reconcile_timeseries,
 )
 from .plexos_utils import (
+    find_xml,
     DATAFILE_COLUMNS,
     PLEXOS_ACTION_MAP,
     filter_property_dates,
@@ -168,20 +169,20 @@ def __init__(self, *args, xml_file: str | None = None, **kwargs) -> None:
         # TODO(pesap): Rename exceptions to include R2X
         # https://github.com/NREL/R2X/issues/5
         # R2X needs at least one of this maps defined to correctly work.
-        if (
-            not self.fuel_map
-            and not self.device_map
-            and not self.device_match_string
-            and not self.category_map
-        ):
-            msg = (
-                "Neither `plexos_fuel_map` or `plexos_device_map` or `device_match_string` was provided. "
-                "To fix, provide any of the mappings."
-            )
+        one_required = ["fuel_map", "device_map", "device_match_string", "category_map"]
+        if all(getattr(self, one_req, {}) == {} for one_req in one_required):
+            msg = f'At least one of {", or ".join(one_required)} is required to initialize PlexosParser'
             raise ParserError(msg)
 
         # Populate databse from XML file.
-        xml_file = xml_file or self.run_folder / self.config.fmap["xml_file"]["fname"]
+        # If xml file is not specified, check user_dict["fmap"]["xml_file"] or use
+        # only xml file in project directory
+        if xml_file is None:
+            xml_file = self.config.fmap.get("xml_file", {}).get("fname", None)
+            xml_file = xml_file or str(find_xml(self.run_folder))
+
+        xml_file = str(self.run_folder / xml_file)
+
         self.db = PlexosSQLite(xml_fname=xml_file)
 
         # Extract scenario data

src/r2x/parser/plexos_utils.py

@@ -6,6 +6,8 @@
 from enum import Enum
 from typing import Any
 from collections.abc import Sequence
+from os import PathLike
+from pathlib import Path
 
 from numpy._typing import NDArray
 import pint
@@ -465,3 +467,42 @@ def time_slice_handler(
                     raise NotImplementedError
 
     return month_datetime_series
+
+
+def find_xml(directory: PathLike):
+    """
+    Parameters
+    ----------
+
+    directory: Pathlike
+        directory to search in for an xml file
+
+    Raises
+    ------
+
+    FileNotFoundError:
+        if no xml file is in <directory>
+        OR more than one xml files are in <directory>
+
+    NotADirectoryError:
+        if <directory> is not a directory
+
+    Returns
+    -------
+    ret: Path
+        Path to a single xml file
+
+    """
+    directory = Path(directory)
+    if not directory.is_dir():
+        raise NotADirectoryError(f"Can't search {directory}, not a directory")
+
+    xml_files = list(directory.glob("*.xml"))
+
+    if len(xml_files) == 0:
+        raise FileNotFoundError(f"No xml file in {directory}")
+
+    if len(xml_files) > 1:
+        raise FileNotFoundError(f"More than one xml file in {directory}")
+
+    return xml_files[0]

tests/test_parser_utils.py

@@ -4,6 +4,7 @@
 from polars.testing import assert_frame_equal
 from tempfile import NamedTemporaryFile
 from r2x.parser.handler import csv_handler
+from r2x.parser.plexos_utils import find_xml
 
 
 @pytest.fixture
@@ -33,3 +34,35 @@ def test_csv_handler_basic(temp_csv_file):
 
     with pytest.raises(FileNotFoundError):
         _ = csv_handler(Path("non_existent_file.csv"))
+
+
+@pytest.fixture
+def basic_xml():
+    data = """
+            <t_category>
+              <category_id>1</category_id>
+              <class_id>1</class_id>
+              <rank>0</rank>
+              <name>-</name>
+            </t_category>
+           """
+    return data
+
+
+def test_find_xml(tmp_path: Path, basic_xml: str):
+    # Case 1: no xml files in tmp_path
+    with pytest.raises(FileNotFoundError):
+        find_xml(tmp_path)
+
+    # Case 2: 1 xml file in tmp_path
+    xml_file_1 = tmp_path / "file1.xml"
+    xml_file_1.write_text(basic_xml)
+
+    assert xml_file_1 == find_xml(tmp_path)
+
+    # Case 3: 2 xml files in tmp_path
+    xml_file_2 = tmp_path / "file2.xml"
+    xml_file_2.write_text(basic_xml)
+
+    with pytest.raises(FileNotFoundError):
+        find_xml(tmp_path)

tests/test_plexos_parser.py

@@ -3,9 +3,9 @@
 from plexosdb import XMLHandler
 from r2x.api import System
 from r2x.config import Scenario
-from r2x.exceptions import ParserError
 from r2x.parser.handler import get_parser_data
 from r2x.parser.plexos import PlexosParser
+from r2x.exceptions import ParserError
 
 DB_NAME = "2-bus_example.xml"
 MODEL_NAME = "main_model"
@@ -58,30 +58,19 @@ def test_build_system(plexos_parser_instance):
     assert isinstance(system, System)
 
 
-def test_raise_if_no_map_provided(tmp_path, data_folder):
-    scenario = Scenario.from_kwargs(
-        name="plexos_test",
-        input_model="plexos",
-        run_folder=data_folder,
-        output_folder=tmp_path,
-        solve_year=2035,
-        model=MODEL_NAME,
-        weather_year=2012,
-        fmap={"xml_file": {"fname": DB_NAME}},
-    )
-    with pytest.raises(ParserError):
-        _ = get_parser_data(scenario, parser_class=PlexosParser)
-
-
 def test_parser_system(pjm_scenario):
     plexos_category_map = {
         "thermal": {"fuel": "GAS", "type": "CC"},
         "solar": {"fuel": "SUN", "type": "WT"},
         "wind": {"fuel": "WIND", "type": "PV"},
     }
-    pjm_scenario.defaults["plexos_category_map"] = plexos_category_map
     pjm_scenario.model = "model_2012"
 
+    with pytest.raises(ParserError):
+        parser = get_parser_data(pjm_scenario, parser_class=PlexosParser)
+
+    pjm_scenario.defaults["plexos_category_map"] = plexos_category_map
+
     parser = get_parser_data(pjm_scenario, parser_class=PlexosParser)
     system = parser.build_system()
     assert isinstance(system, System)