011: Testing Strategy¶

Type: Operational
Status: Planned
Date: YYYY-MM-DD
Author(s) / Deciders: Test engineers, software architects, and core contributors
Question: How are automated and manual tests organized across unit, integration, and end-to-end boundaries, and what coverage standards govern quality verification?

Context¶

Reliable software requires an explicit verification strategy that balances execution speed, implementation cost, and failure detection confidence. Ad-hoc testing leads to brittle integration suites, untested edge cases, and regressions. Defining testing tiers, white-box and black-box boundaries, and acceptance criteria early gives developers objective quality targets.

Test Pyramid and Tier Organization¶

Structure test suites across three primary tiers:

Tier	Scope and Purpose	Execution Target	Typical Location
Unit Tests	Fast, isolated verification of individual functions, modules, and classes.	Sub-second per module.	Co-located in `source/` or `tests/unit/`.
Integration Tests	Verification of inter-module boundaries, database queries, network protocols, or IPC interfaces.	Seconds.	`tests/integration/`.
End-to-End (E2E) / System Tests	Full workflow verification from user input or CLI invocation through all runtime dependencies.	Minutes.	`tests/e2e/`.

White-Box and Black-Box Testing Boundaries¶

White-Box Testing¶

Scope: Internal logic, branch conditions, private methods, and error recovery paths with full visibility into the source code.
Application: Unit tests and algorithmic validation where exhaustive internal state exploration is necessary.

Black-Box Testing¶

Scope: External interfaces, public API endpoints, CLI argument parsing, and input/output contracts with zero reliance on internal implementation details.
Application: Integration, API contract, and acceptance testing ensuring stability across internal refactoring.

Requirements and Restrictions¶

Coverage and Verification Thresholds¶

Coverage Targets: Specify target branch and line coverage percentages (for example, 80% minimum on core business logic).
Flakiness Policy: Non-deterministic tests MUST NOT be merged into master or tolerated in continuous integration; flaky tests must be quarantined or rewritten immediately.
Regression Mandate: Every bug fix SHOULD be accompanied by an automated regression test reproducing the original defect.

Manual Exploratory Testing¶

Acceptance Criteria: Human verification protocols for user interface aesthetics, exploratory accessibility audits, and novel interaction paradigms that cannot be captured cleanly through automated asserts.
Traceability: Acceptance test scenarios MUST map directly to Feature Records and Requirements.

Alternatives¶

End-to-End Heavy Strategy (Ice Cream Cone): Relying primarily on top-level system tests catches high-level defects but results in slow, flaky, and expensive test runs.
Unit Tests Only: Fast and easy to write, but leaves inter-service communication and real-world configuration errors undetected.
Manual-Only Verification: Zero upfront automation cost, but creates massive regression bottlenecks and human error as the codebase expands.

Decision¶

Document the chosen test frameworks, directory layout under tests/, minimum coverage thresholds, and manual acceptance protocols.

Consequences¶

Positives¶

Clear division between fast local unit feedback and comprehensive integration validation.
Standardized testing conventions prevent regressions and simplify automated pull request reviews.

Negatives¶

Maintaining high test coverage requires continuous effort and disciplined mock management.