An engineering question may span several models without requiring one larger stored model. Keep question-specific representations separate and join them through stable identities when a cross-model property must be evaluated.
Engineering question. Does an important user journey exercise its declared endpoints, receive the required test coverage and placement, and execute under the correct host policy?
Figure C.6-1.Composition by reference. Stable identities join the user-journey, service, coverage, test-placement, and execution-policy views. The resulting joined view supports cross-model queries without duplicating those facts into a single stored model.
Property. The joined view states cross-model properties that no single view can:
Every declared journey step has the required test coverage.
Declared journey dependencies agree with the actual call sites.
Declared endpoints are exercised.
Test placement reflects journey criticality.
Execution respects the selected host policy.
The reusable pattern. State the engineering question, select the relevant views, join them on stable identities, and evaluate the cross-view property. The scenario is a traversal across representations, not an additional stored model.