Test Strategy

Purpose

Select one owning test per behavioral claim at the boundary where the claim is observable, as testing defines. Candidate discovery does not create an obligation to implement every technically valid test.

Selection Process

For each acceptance criterion that may require integration or E2E proof:

1. Name the observable boundary: Identify the interaction, persisted effect, process, or user journey that must be proven.
2. Check the existing owner: When an established test owns the claim at that boundary with assertions that detect its material failure, update it rather than adding another.
3. Select the owning level:
   • use integration when the behavior is observable at a component, persistence, or process boundary;
   • use E2E when the behavior is observable only across the complete journey;
   • leave the cases of a calculation, parsing, or branching rule inside the behavior to that rule's unit test.
4. Compare cost: Consider setup, execution time, brittleness, maintenance, and diagnostic value using repository evidence rather than fixed universal scores.
5. Retain valuable proof: Select a new test only when its regression-detection value justifies that cost.

No new integration or E2E test is a valid conclusion when existing tests already own each claim.

Priority

Prioritize proof for:

• core user or consumer journeys;
• shared or public contracts;
• persisted state transitions;
• security, authorization, compliance, or irreversible effects;
• integrations with demonstrated failure risk.

Priority does not determine test level. Use the narrowest boundary that can observe the prioritized behavior.

Deduplication

Before adding a test:

• search the existing suite for equivalent behavior;
• identify overlapping proof at other levels;
• extend existing coverage when that remains clear and maintainable;
• keep one representative proof when several candidates observe the same risk.

Selection Record

Record only decisions needed by planning or review:

Acceptance criterion: [identifier or behavior]
Selected proof: existing | unit | integration | E2E | none
Boundary observed: [observable interaction or result]
Reason: [why this test owns the claim at this boundary]

Completion Check

• Every selected test traces to an observable requirement or accepted contract.
• Each claim has one owning test, and an existing owner was updated rather than duplicated.