fix: exclude integration tests from CI — require pytest -m integration to run

- Add `integration` marker to `test_data_diff_integration.py`
- Configure `pyproject.toml` to skip integration tests by default
- Integration tests require Docker Postgres and matching `altimate-core` build

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: suryaiyer95

packages/altimate-engine/pyproject.toml

@@ -32,6 +32,8 @@ dev = ["pytest>=7.0", "ruff>=0.1"]
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]
+markers = ["integration: requires real databases (DuckDB files, Docker Postgres)"]
+addopts = "-m 'not integration'"
 
 [tool.hatch.build.targets.wheel]
 packages = ["src/altimate_engine"]

packages/altimate-engine/tests/test_data_diff_integration.py

@@ -32,9 +32,10 @@
 except ImportError:
     RELADIFF_AVAILABLE = False
 
-pytestmark = pytest.mark.skipif(
-    not RELADIFF_AVAILABLE, reason="altimate-core not installed"
-)
+pytestmark = [
+    pytest.mark.integration,
+    pytest.mark.skipif(not RELADIFF_AVAILABLE, reason="altimate-core not installed"),
+]
 
 from altimate_engine.connections import ConnectionRegistry
 from altimate_engine.sql.data_diff import run_data_diff