rewrite test_cli.py and add conftest.py following fre-cli conftest pattern

Fixes:
- test_cli_fremor: click>=8.2 returns exit_code=2 for group with no subcommand
- log tests: use 'yaml --help' so group callback runs before click processes --help
- run/varlist tests: use session-scoped conftest fixtures for NC file generation
- run/varlist tests: use tmp_path for outputs instead of shared directories
- config test: depend on cli_sos_nc_file fixture
- find tests: use Path objects from conftest instead of string concatenation

Agent-Logs-Url: https://github.com/ilaflott/fremorizer/sessions/8457b2f7-ba78-41c0-b74e-2ec0575b97d9

Co-authored-by: ilaflott <[email protected]>

Author: Copilot

fremorizer/tests/conftest.py

@@ -0,0 +1,67 @@
+'''
+Shared fixtures for fremorizer/tests CLI integration tests.
+'''
+
+from datetime import date
+from pathlib import Path
+import shutil
+import subprocess
+
+import pytest
+
+import fremorizer
+
+
+# ── path constants ──────────────────────────────────────────────────────────
+ROOTDIR = Path(fremorizer.__file__).parent / 'tests' / 'test_files'
+
+CMIP6_TABLE_CONFIG = ROOTDIR / 'cmip6-cmor-tables' / 'Tables' / 'CMIP6_Omon.json'
+CMIP7_TABLE_CONFIG = ROOTDIR / 'cmip7-cmor-tables' / 'tables' / 'CMIP7_ocean.json'
+
+INDIR = ROOTDIR / 'ocean_sos_var_file'
+VARLIST = ROOTDIR / 'varlist'
+VARLIST_DIFF = ROOTDIR / 'varlist_local_target_vars_differ'
+EXP_CONFIG = ROOTDIR / 'CMOR_input_example.json'
+EXP_CONFIG_CMIP7 = ROOTDIR / 'CMOR_CMIP7_input_example.json'
+
+SOS_NC_FILENAME = 'reduced_ocean_monthly_1x1deg.199301-199302.sos.nc'
+SOSV2_NC_FILENAME = 'reduced_ocean_monthly_1x1deg.199301-199302.sosV2.nc'
+
+YYYYMMDD = date.today().strftime('%Y%m%d')
+
+
+# ── ncgen helper ────────────────────────────────────────────────────────────
+def _ncgen(cdl_name, nc_path):
+    """Run ncgen3 to convert a CDL file into a NetCDF-4 file."""
+    cdl_path = ROOTDIR / 'reduced_ascii_files' / cdl_name
+    assert cdl_path.exists(), f'CDL file not found: {cdl_path}'
+
+    if nc_path.exists():
+        nc_path.unlink()
+
+    subprocess.run(
+        ['ncgen3', '-k', 'netCDF-4', '-o', str(nc_path), str(cdl_path)],
+        check=True,
+    )
+    assert nc_path.exists(), f'ncgen3 failed to create {nc_path}'
+
+
+# ── session-scoped fixtures ─────────────────────────────────────────────────
+@pytest.fixture(scope='session')
+def cli_sos_nc_file():
+    """Generate the sos NetCDF file from CDL (session-scoped)."""
+    INDIR.mkdir(parents=True, exist_ok=True)
+    nc_path = INDIR / SOS_NC_FILENAME
+    _ncgen('reduced_ocean_monthly_1x1deg.199301-199302.sos.cdl', nc_path)
+    return str(nc_path)
+
+
+@pytest.fixture(scope='session')
+def cli_sosv2_nc_file(cli_sos_nc_file):
+    """Create a copy of the sos file as sosV2 (session-scoped)."""
+    nc_path = INDIR / SOSV2_NC_FILENAME
+    if nc_path.exists():
+        nc_path.unlink()
+    shutil.copy(cli_sos_nc_file, str(nc_path))
+    assert nc_path.exists()
+    return str(nc_path)