Convert tests from unittest to pytest format

pyproject.toml

@@ -33,7 +33,8 @@ dependencies = [
 
 [project.optional-dependencies]
 test = [
-  "pytest",
+  "pytest>=7.0.0",
+  "pytest-cov>=4.0.0",
   "xarray[io]",
   "gcsfs",
 ]
@@ -57,6 +58,29 @@ pyink-use-majority-quotes = true
 
 [tool.setuptools_scm]
 
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+python_files = ["test_*.py"]
+python_classes = ["Test*"]
+python_functions = ["test_*"]
+addopts = [
+    "-v",
+    "--tb=short",
+    "--strict-markers",
+    "--disable-warnings",
+]
+markers = [
+    "unit: Unit tests",
+    "integration: Integration tests", 
+    "slow: Slow tests",
+    "memory: Memory-intensive tests",
+    "gcs: Tests requiring GCS access",
+]
+filterwarnings = [
+    "ignore::DeprecationWarning",
+    "ignore::PendingDeprecationWarning",
+]
+
 [dependency-groups]
 dev = [
     "xarray_sql[test]",

xarray_sql/df_integrationtest.py

@@ -1,13 +1,18 @@
-import unittest
+"""Integration tests for xarray-sql."""
 
+import pytest
 import xarray as xr
 
 from . import read_xarray
 
 
-class Era5TestCast(unittest.TestCase):
+class TestEra5Integration:
+  """Test integration with ERA5 dataset."""
 
+  @pytest.mark.integration
+  @pytest.mark.gcs
   def test_open_era5(self):
+    """Test opening ERA5 dataset from Google Cloud Storage."""
     era5_ds = xr.open_zarr(
         'gs://gcp-public-data-arco-era5/ar/1959-2022-full_37-1h-0p25deg-chunk-1.zarr-v2',
         chunks={'time': 240, 'level': 1},
@@ -16,14 +21,12 @@ def test_open_era5(self):
         era5_ds[['u_component_of_wind', 'v_component_of_wind']]
     )
 
-    self.assertEqual(
-        list(era5_wind_df.columns),
-        [
-            'time',
-            'level',
-            'latitude',
-            'longitude',
-            'u_component_of_wind',
-            'v_component_of_wind',
-        ],
-    )
+    expected_columns = [
+        'time',
+        'level',
+        'latitude',
+        'longitude',
+        'u_component_of_wind',
+        'v_component_of_wind',
+    ]
+    assert list(era5_wind_df.columns) == expected_columns