Tests are selected by the impact of a change, derived from what each case declares it reads, and a change of unknown impact runs every case

majordomus://adr/adr-0187proposed derive-performancechatgpt-project

it references

put_in_force scripts/ci-plan (file)
put_in_force test/run.sh (file)
put_in_force adr-0026
put_in_force adr-0037
put_in_force adr-0186
put_in_force a-change-is-judged-in-minutes (intent)
put_in_force I3238
put_in_force I3240
put_in_force do-less-work-before-doing-it-faster (knowledge)
put_in_force a-change-is-judged-in-minutes
put_in_force project.blocking-checks-cheap@1

referenced by

Nothing in the layer names it. Backlinks are derived, so an empty list is an answer rather than an omission.

187. Tests are selected by the impact of a change, derived from what each case declares it reads, and a change of unknown impact runs every case

Context

Gates are selected by hand-kept path classes; cases are not selected at all. 431 of 527 cases carry # majordomus-covers: (282 'none').

A case's reads are declared in its header or derived from the commands and features it covers through the feature-to-module map (ADR 0026). scripts/ci-plan computes the closure from changed paths to cases and lists each selection with its reason. A case that declares nothing is always selected. A mutation case proves that a case whose input changed is never skipped. Historical shard timing balances shards but never selects.

Alternatives rejected

Manual giant path lists (c195#2)
Sharding by historical time as the only lever (c228#3)

Consequences

Selection starts conservative (282 'none' cases always run) and narrows only as cases declare. The full suite stays on the proof lane.

Sources

Promoted on 2026-10-18 from the owner's ChatGPT project (workspace chatgpt-majordomus, issue I3100). The owner has not accepted it; it is proposed for the owner's decision.

chatgpt-majordomus:c130#3
chatgpt-majordomus:c195#2
chatgpt-majordomus:c228#3

Where this comes from

canonical file: .ai/repo/adrs/0187-tests-are-selected-by-the-impact-of-a-change-derived-from-what-e.md
identity: adr-0187
also served as: MCP resource majordomus://adr/adr-0187 · majordomus entity show adr/adr-0187 · GET /api/v1/entity?uri=majordomus://adr/adr-0187
in the Cockpit: /cockpit/objects/adr/adr-0187

This page is generated from the file above by scripts/generate-site-data; editing the page changes nothing, editing the file changes every surface. The relations above are edges of docs/generated/graph.json, which the executable writes from the same index.