PIK-LPJmL · zner0L · Jun 23, 2025 · Jul 1, 2025 · Jul 2, 2025 · Jul 2, 2025
diff --git a/pycoupler/coupler.py b/pycoupler/coupler.py
@@ -799,6 +799,8 @@ def _copy_input(self, start_year, end_year):
             start_year = self.config.start_coupling - 1
         if end_year is None:
             end_year = self.config.start_coupling - 1
+        if start_year > end_year:
+            raise ValueError("start_year cannot be later than end_year")
 
         # iterate over each inputs to be send via sockets (get initial values)
         for key in sock_inputs:
@@ -823,17 +825,26 @@ def _copy_input(self, start_year, end_year):
 
             # determine start cut off and end cut off year
             if meta_data.firstyear > end_year:
+                # data is after simulation period
                 cut_start_year = meta_data.firstyear
                 cut_end_year = meta_data.firstyear
             elif meta_data.lastyear < start_year:
+                # data is before simulation period
                 cut_start_year = meta_data.lastyear
                 cut_end_year = meta_data.lastyear
             elif meta_data.firstyear >= start_year:
+                # data begins in simulation period
                 cut_start_year = meta_data.firstyear
                 cut_end_year = min(meta_data.lastyear, end_year)
             elif meta_data.lastyear < end_year:
+                # data ends in simulation period
                 cut_start_year = start_year
                 cut_end_year = meta_data.lastyear
+            elif meta_data.firstyear <= start_year and meta_data.lastyear >= start_year:
+                # data starts before simulation period,
+                # but simulation is within data period
+                cut_start_year = start_year
+                cut_end = cut_end_year = min(meta_data.lastyear, end_year)
 
             cut_clm_start = [
                 f"{self._config.model_path}/bin/cutclm",

diff --git a/tests/conftest.py b/tests/conftest.py
@@ -1,22 +1,30 @@
 import os
 import pytest
+from pycoupler.coupler import LPJmLCoupler
 
 
-def get_test_path():
+@pytest.fixture
+def test_path():
     """Fixture for the test path."""
     return os.path.dirname(os.path.abspath(__file__))
 
 
 @pytest.fixture
-def test_path():
-    """Fixture for the test path."""
-    return get_test_path()
+def lpjml_coupler(test_path):
+    config_coupled_fn = f"{test_path}/data/config_coupled_test.json"
+    # Using yield enables safe teardown of the fixture
+    # (see https://docs.pytest.org/en/stable/how-to/fixtures.html#safe-teardowns)
+    yield LPJmLCoupler(config_file=config_coupled_fn)
+    # Reset test line env variable
+    os.environ["TEST_LINE_COUNTER"] = "0"
 
 
 def pytest_configure(config):
     import sys
 
     sys._called_from_test = True
+    os.environ["TEST_PATH"] = os.path.dirname(os.path.abspath(__file__))
+    os.environ["TEST_LINE_COUNTER"] = "0"
 
 
 def pytest_unconfigure(config):

diff --git a/tests/data/input/with_tillage.nc.json b/tests/data/input/with_tillage.nc.json
@@ -1,30 +1,33 @@
 {
-  "sim_name" : "coupled_test",
-  "source" : "LPJmL C Version 5.8.1",
-  "history" : "/p/projects/open/Jannes/copan_core/lpjml/LPJmL_internal/bin/lpjml /p/projects/open/Jannes/copan_core/lpjml/config_coupled_test.json",
-  "variable" : "grid",
-  "firstcell" : 27410,
-  "ncell" : 2,
-  "cellsize_lon" : 0.500000,
-  "cellsize_lat" : 0.500000,
-  "nstep" : 1,
-  "timestep" : 1,
-  "nbands" : 2,
-  "long_name" : "tillage",
-  "unit" : "",
-  "firstyear" : 2022,
-  "lastyear" : 2022,
-  "nyear" : 1,
-  "datatype" : "short",
-  "scalar" : 1,
-  "order" : "cellyear",
-  "bigendian" : false,
-  "format" : "cdf",
-  "ref_area" : {"filename" : "with_tillage.nc4.json", "format" : "meta"},
-  "filename" : "with_tillage.nc4",
+  "sim_name": "coupled_test",
+  "source": "LPJmL C Version 5.8.1",
+  "history": "/p/projects/open/Jannes/copan_core/lpjml/LPJmL_internal/bin/lpjml /p/projects/open/Jannes/copan_core/lpjml/config_coupled_test.json",
+  "variable": "grid",
+  "firstcell": 27410,
+  "ncell": 2,
+  "cellsize_lon": 0.500000,
+  "cellsize_lat": 0.500000,
+  "nstep": 1,
+  "timestep": 1,
+  "nbands": 2,
+  "long_name": "tillage",
+  "unit": "",
+  "firstyear": 2000,
+  "lastyear": 2022,
+  "nyear": 1,
+  "datatype": "short",
+  "scalar": 1,
+  "order": "cellyear",
+  "bigendian": false,
+  "format": "cdf",
+  "ref_area": {
+    "filename": "with_tillage.nc4.json",
+    "format": "meta"
+  },
+  "filename": "with_tillage.nc4",
   "global_attrs": {
-    "institution":"PIK Potsdam",
-    "contact":"Jane Doe",
+    "institution": "PIK Potsdam",
+    "contact": "Jane Doe",
     "comment": "check"
   }
-}
+}
diff --git a/tests/test_couple.py b/tests/test_couple.py
@@ -1,22 +1,10 @@
 """Test the LPJmLCoupler class."""
 
-import os
 import numpy as np
-from unittest.mock import patch
-from copy import deepcopy
-from pycoupler.coupler import LPJmLCoupler
+import pytest
 
 
-from .conftest import get_test_path
-
-
-@patch.dict(os.environ, {"TEST_PATH": get_test_path(), "TEST_LINE_COUNTER": "0"})
-def test_lpjml_coupler(test_path):
-
-    config_coupled_fn = f"{test_path}/data/config_coupled_test.json"
-    lpjml_coupler = LPJmLCoupler(config_file=config_coupled_fn)
-
-    """Test the LPJmLCoupler class."""
+def test_lpjml_coupler(test_path, lpjml_coupler):
     inputs = lpjml_coupler.read_input(copy=False)
     outputs = lpjml_coupler.read_historic_output()
 
@@ -55,24 +43,45 @@ def test_lpjml_coupler(test_path):
     assert lpjml_coupler.sim_years == []
     assert lpjml_coupler.coupled_years == []
     assert [year for year in lpjml_coupler.get_coupled_years()] == []
-
-    second_coupler = deepcopy(lpjml_coupler)
-    lpjml_coupler.code_to_name(to_iso_alpha_3=False)
-    assert lpjml_coupler.country[0].item() == "Germany"
-    second_coupler.code_to_name(to_iso_alpha_3=True)
-    assert second_coupler.country[0].item() == "DEU"
-
     assert (
         repr(lpjml_coupler)
         == f"<pycoupler.LPJmLCoupler>\nSimulation:  (version: 3, localhost:<none>)\n  * sim_year   2050\n  * ncell      2\n  * ninput     1\nConfiguration:\n  Settings:      lpjml v5.8\n    (general)\n    * sim_name   coupled_test\n    * firstyear  2001\n    * lastyear   2050\n    * startgrid  27410\n    * endgrid    27411\n    * landuse    yes\n    (changed)\n    * model_path           LPJmL_internal\n    * sim_path             {test_path}/data/\n    * outputyear           2022\n    * output_metafile      True\n    * write_restart        False\n    * nspinup              0\n    * float_grid           True\n    * restart_filename     restart/restart_historic_run.lpj\n    * outputyear           2022\n    * radiation            cloudiness\n    * fix_co2              True\n    * fix_co2_year         2018\n    * fix_climate          True\n    * fix_climate_cycle    11\n    * fix_climate_year     2013\n    * river_routing        False\n    * tillage_type         read\n    * residue_treatment    fixed_residue_remove\n    * double_harvest       False\n    * intercrop            True\n    * sim_path             {test_path}/data/\n  Coupled model:        copan:CORE\n    * start_coupling    2023\n    * input (coupled)   ['with_tillage']\n    * output (coupled)  ['grid', 'pft_harvestc', 'cftfrac', 'soilc_agr_layer', 'hdate', 'country', 'region']\n  "  # noqa
     )
 
 
-@patch.dict(os.environ, {"TEST_PATH": get_test_path(), "TEST_LINE_COUNTER": "0"})
-def test_copy_input(test_path):
+def test_lpjml_coupler_codes_name(lpjml_coupler):
+    lpjml_coupler.code_to_name(to_iso_alpha_3=False)
+    assert lpjml_coupler.country[0].item() == "Germany"
 
-    config_coupled_fn = f"{test_path}/data/config_coupled_test.json"
-    lpjml_coupler = LPJmLCoupler(config_file=config_coupled_fn)
 
-    inputs = lpjml_coupler.read_input(copy=False)
-    assert lpjml_coupler._copy_input(start_year=2022, end_year=2022) == "tested"
+def test_lpjml_coupler_codes_iso(lpjml_coupler):
+    lpjml_coupler.code_to_name(to_iso_alpha_3=True)
+    assert lpjml_coupler.country[0].item() == "DEU"
+
+
+# Test all period combination cases (data period is 2000 to 2022)
+@pytest.mark.parametrize(
+    "start_year,end_year",
+    [
+        (2005, 2015),
+        (1980, 1998),
+        (2024, 2025),
+        (1998, 2025),
+        (1998, 2020),
+        (2020, 2025),
+        (None, 2024),
+        (1998, None),
+        (None, None),
+        pytest.param(
+            2025,
+            1998,
+            marks=pytest.mark.xfail(
+                raises=pytest.raises(
+                    ValueError, match="start_year cannot be later than end_year"
+                )
+            ),
+        ),
+    ],
+)
+def test_lpjml_coupler_copy_input_(test_path, lpjml_coupler, start_year, end_year):
+    assert lpjml_coupler._copy_input(start_year, end_year) == "tested"
diff --git a/tests/test_data.py b/tests/test_data.py
@@ -1,8 +1,6 @@
 """Test the LPJmLData class."""
 
-import os
 import numpy as np
-from unittest.mock import patch
 
 from pycoupler.data import (
     read_data,
8CC7
@@ -12,8 +10,6 @@
     LPJmLInputType,
     append_to_dict,
 )
-from pycoupler.coupler import LPJmLCoupler
-from .conftest import get_test_path
 
 
 def test_read_data(test_path):
@@ -44,14 +40,7 @@ def test_dataset(test_path):
     assert list(data_dict.keys()) == ["with_tillage"]
 
 
-@patch.dict(
-    os.environ, {"TEST_PATH": get_test_path(), "TEST_LINE_COUNTER": "0"}
-)  # noqa
-def test_get_neighbourhood(test_path):
-
-    config_coupled_fn = f"{test_path}/data/config_coupled_test.json"
-    lpjml_coupler = LPJmLCoupler(config_file=config_coupled_fn)
-
+def test_get_neighbourhood(lpjml_coupler):
     neighbourhood = lpjml_coupler.grid.get_neighbourhood().values
 
     test_neighbours = np.array(