Selection Engine

Purpose

The selection computation — evaluating the change set against the transitive-closure transpose to produce the affected test set.

Requirements

Requirement: TIA-SEL-001 — Affected set computation

When a change set is supplied, the selector SHALL compute the affected set as the union of the transpose-closure of Δ and the always-run set.

Scenario: Basic selection

• GIVEN a change set Δ and an always-run set
• WHEN selection is invoked
• THEN the selector SHALL compute affected = Δ · (D*)ᵀ ∪ always_run

Requirement: TIA-SEL-002 — Component scoped traversal

The selector SHALL scope reverse traversal to components reachable from the change set before enumerating candidate tests.

Scenario: Scoped traversal

• GIVEN a change set in component A
• WHEN computing selection
• THEN the selector SHALL only traverse components reachable from A
• AND SHALL NOT traverse unrelated components

Requirement: TIA-SEL-003 — Semiring-specific selection

Where a semiring is specified, the selector SHALL evaluate the same selection query in that semiring (Boolean → affected set, Viterbi → confidence, tropical → change-to-test distance, cost → expected duration).

Scenario: Semiring evaluation

• GIVEN a specified semiring type
• WHEN the selector evaluates the query
• THEN it SHALL produce results in that semiring (e.g. Boolean for affected set, Viterbi for confidence)

Requirement: TIA-SEL-004 — Static edge retention

The selector SHALL never remove a static edge from consideration on the grounds that runtime evidence did not confirm it.

Scenario: Static edge always considered

• GIVEN a static edge and runtime evidence that does not confirm it
• WHEN selection is computed
• THEN the static edge SHALL remain in consideration
• AND SHALL NOT be removed

Requirement: TIA-SEL-005 — Deterministic ordering

Where deterministic ordering is requested, the selector SHALL emit the affected set in a stable, reproducible order.

Scenario: Stable ordering

• GIVEN identical inputs and store state
• WHEN deterministic ordering is requested
• THEN the selector SHALL produce an identical ordering of affected tests

Requirement: TIA-SEL-006 — Duration ordering

Where a duration ordering is requested, the selector SHALL order selected tests by descending recorded mean duration.

Scenario: Duration-based sort

• GIVEN a request for duration ordering
• WHEN the selector emits the affected set
• THEN it SHALL order tests by descending recorded mean duration

Requirement: TIA-SEL-007 — Predictive ranking constraints

Where predictive ranking is enabled, the selector SHALL apply ranking only as a re-ordering or cap over the already-computed recall-safe affected set, and SHALL NOT remove any always-run member.

Scenario: Ranking preserves recall

• GIVEN predictive ranking is enabled
• WHEN selection is computed
• THEN ranking SHALL only re-order or cap the affected set
• AND SHALL NOT remove any always-run member

Requirement: TIA-SEL-008 — Ordering flag value validation

The CLI SHALL validate the value of the --ordering flag against an enumerated set of recognized values. If an unrecognized value is supplied, the CLI SHALL emit an error listing the valid values and SHALL NOT silently default to any behavior. The CLI SHALL use the same validation mechanism used for other enum-style flags (e.g. mutual-exclusivity groups for --agent/--json/--pre-edit).

Scenario: Recognized ordering value

• GIVEN an ordering value "deterministic"
• WHEN --ordering deterministic is passed
• THEN the CLI SHALL accept the value
• AND SHALL apply the corresponding ordering

Scenario: Unrecognized ordering value

• GIVEN an ordering value "banana"
• WHEN --ordering banana is passed
• THEN the CLI SHALL emit an error
• AND SHALL list valid values in the error message
• AND SHALL NOT silently fall back to a default ordering