Add conftest.py with fixture for simplemind Session

tests/conftest.py

@@ -0,0 +1,15 @@
+import pytest
+
+import os
+import sys
+
+# Add the project root to the Python path.
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from simplemind import Session
+
+
+@pytest.fixture
+def sm():
+    """Fixture that provides a simplemind Session instance with default settings."""
+    return Session()