feat: implement linting and testing

tests/conftest.py

@@ -0,0 +1,35 @@
+"""Shared test fixtures."""
+
+from unittest.mock import MagicMock
+
+
+def make_mock_engine(select_rows: list[tuple] | None = None):
+    """Return a mock SQLAlchemy engine.
+
+    Args:
+        select_rows: Rows to return from *connect()* (SELECT queries).
+            Defaults to an empty list.
+    """
+    select_rows = select_rows or []
+
+    engine = MagicMock()
+
+    # engine.begin() context manager → conn for DDL / writes
+    write_conn = MagicMock()
+    engine.begin.return_value.__enter__ = MagicMock(return_value=write_conn)
+    engine.begin.return_value.__exit__ = MagicMock(return_value=False)
+
+    # engine.connect() context manager → conn for SELECTs
+    read_conn = MagicMock()
+    read_conn.execute.return_value = iter(select_rows)
+    engine.connect.return_value.__enter__ = MagicMock(return_value=read_conn)
+    engine.connect.return_value.__exit__ = MagicMock(return_value=False)
+
+    return engine, write_conn, read_conn
+
+
+def make_mock_listing(data: dict):
+    """Return a mock pyfunda Listing-like object."""
+    listing = MagicMock()
+    listing.to_dict.return_value = data
+    return listing