better dfn access pattern for tests

Author: wpbonelli

test/conftest.py

@@ -1,7 +1,9 @@
+import os
 from pathlib import Path
 from platform import system
 
 import pytest
+from modflow_devtools.download import download_and_unzip
 from modflow_devtools.misc import is_in_ci
 
 pytest_plugins = ["modflow_devtools.fixtures"]
@@ -12,6 +14,44 @@
 EXCLUDED_EXAMPLES = []
 
 
+def _get_dfn_path(tmp_path_factory):
+    """Get path to MF6 DFN files, checking local repos or downloading if needed."""
+
+    # Check REPOS_PATH environment variable (modflow-devtools convention)
+    repos_path = os.environ.get("REPOS_PATH")
+    if repos_path:
+        dfn_path = Path(repos_path) / "modflow6" / "doc" / "mf6io" / "mf6ivar" / "dfn"
+        if dfn_path.exists():
+            return dfn_path
+
+    # Check if modflow6 repo exists as sibling to this project
+    sibling_path = PROJ_ROOT_PATH.parent / "modflow6" / "doc" / "mf6io" / "mf6ivar" / "dfn"
+    if sibling_path.exists():
+        return sibling_path
+
+    # Download from GitHub if not found locally
+    tmp_dir = tmp_path_factory.mktemp("mf6_dfn")
+    url = "https://github.com/MODFLOW-USGS/modflow6/archive/refs/heads/develop.zip"
+    download_and_unzip(url, tmp_dir, verbose=False)
+
+    # Find the extracted directory (will have a prefix like 'modflow6-develop')
+    extracted_dirs = [d for d in tmp_dir.iterdir() if d.is_dir() and d.name.startswith("modflow6")]
+    if not extracted_dirs:
+        pytest.fail(f"Failed to extract modflow6 from {url}")
+
+    dfn_path = extracted_dirs[0] / "doc" / "mf6io" / "mf6ivar" / "dfn"
+    if not dfn_path.exists():
+        pytest.fail("DFN directory not found in downloaded modflow6 repo")
+
+    return dfn_path
+
+
+@pytest.fixture(scope="session")
+def dfn_path(tmp_path_factory):
+    """Get the path to MF6 DFN files."""
+    return _get_dfn_path(tmp_path_factory)
+
+
 @pytest.fixture(scope="session", autouse=True)
 def patch_macos_ci_matplotlib():
     # use noninteractive matplotlib backend if in Mac OS CI to avoid pytest-xdist node failure

test/test_mf6_reader.py

@@ -288,11 +288,11 @@ def test_parse_gwf_wel_file(model_workspace):
 
 
 @pytest.mark.parametrize("model_workspace", ["mf6/example/ex-gwf-csub-p01"], indirect=True)
-def test_transform_gwf_ic_file(model_workspace):
+def test_transform_gwf_ic_file(model_workspace, dfn_path):
     """Test transforming a parsed GWF IC file into structured data."""
 
     # Load the DFN for IC
-    dfns = load_flat("../modflow-devtools/autotest/temp/dfn/toml")
+    dfns = load_flat(dfn_path)
     ic_dfn = dfns["gwf-ic"]
 
     # Find the IC file
@@ -317,11 +317,11 @@ def test_transform_gwf_ic_file(model_workspace):
 
 
 @pytest.mark.parametrize("model_workspace", ["mf6/example/ex-gwf-bcf2ss-p01a"], indirect=True)
-def test_transform_gwf_wel_file(model_workspace):
+def test_transform_gwf_wel_file(model_workspace, dfn_path):
     """Test transforming a parsed GWF WEL file into structured data."""
 
     # Load the DFN for WEL
-    dfns = load_flat("../modflow-devtools/autotest/temp/dfn/toml")
+    dfns = load_flat(dfn_path)
     wel_dfn = dfns["gwf-wel"]
 
     # Find the WEL file