feat(rulebook): service layer — subscriptions + get_applicable_rules

tests/test_services_rulebooks.py

@@ -221,3 +221,69 @@ async def test_get_rule_returns_none_when_not_owner():
         from fabledassistant.services.rulebooks import get_rule
         result = await get_rule(rule_id=1, user_id=99)
     assert result is None
+
+
+# ── Subscriptions + applicable_rules ────────────────────────────────────
+
+@pytest.mark.asyncio
+async def test_subscribe_project_requires_owned_rulebook():
+    """subscribe_project raises if user doesn't own the rulebook."""
+    mock_session = _make_mock_session()
+    mock_result = MagicMock()
+    mock_result.scalar_one_or_none.return_value = None
+    mock_session.execute = AsyncMock(return_value=mock_result)
+    with patch("fabledassistant.services.rulebooks.async_session") as mock_cls:
+        mock_cls.return_value = mock_session
+        from fabledassistant.services.rulebooks import subscribe_project
+        with pytest.raises(ValueError, match="not found"):
+            await subscribe_project(
+                project_id=1, rulebook_id=999, user_id=7,
+            )
+
+
+@pytest.mark.asyncio
+async def test_get_applicable_rules_returns_shape():
+    """get_applicable_rules returns {rules, truncated, subscribed_rulebooks}."""
+    mock_session = _make_mock_session()
+    sub_result = MagicMock()
+    sub_result.all.return_value = [(1, "FabledSword family")]
+    rules_result = MagicMock()
+    rules_result.all.return_value = [
+        (i, f"Rule {i}", f"Statement {i}", "git-workflow", "FabledSword family")
+        for i in range(50)
+    ]
+    mock_session.execute = AsyncMock(side_effect=[sub_result, rules_result])
+
+    with patch("fabledassistant.services.rulebooks.async_session") as mock_cls:
+        mock_cls.return_value = mock_session
+        from fabledassistant.services.rulebooks import get_applicable_rules
+        result = await get_applicable_rules(project_id=3, user_id=7, limit=50)
+
+    assert "rules" in result
+    assert "truncated" in result
+    assert "subscribed_rulebooks" in result
+    assert result["subscribed_rulebooks"] == [{"id": 1, "title": "FabledSword family"}]
+    assert len(result["rules"]) == 50
+    assert result["truncated"] is False  # exactly 50, not over
+
+
+@pytest.mark.asyncio
+async def test_get_applicable_rules_truncates_when_over_limit():
+    """When limit+1 rows are returned, truncated=True and only `limit` returned."""
+    mock_session = _make_mock_session()
+    sub_result = MagicMock()
+    sub_result.all.return_value = []
+    rules_result = MagicMock()
+    # 51 rows means truncation detected
+    rules_result.all.return_value = [
+        (i, f"r{i}", "stmt", "topic", "rb") for i in range(51)
+    ]
+    mock_session.execute = AsyncMock(side_effect=[sub_result, rules_result])
+
+    with patch("fabledassistant.services.rulebooks.async_session") as mock_cls:
+        mock_cls.return_value = mock_session
+        from fabledassistant.services.rulebooks import get_applicable_rules
+        result = await get_applicable_rules(project_id=3, user_id=7, limit=50)
+
+    assert result["truncated"] is True
+    assert len(result["rules"]) == 50