Increase default parallelism for unit and integration test nox sessions #1719

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opened 2026-04-02 23:35:27 +00:00 by freemo · 1 comment

freemo commented

2026-04-02 23:35:27 +00:00

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Branch: task/m9-increase-test-parallelism
Commit Message: chore(nox): increase default parallelism for unit and integration test sessions
Milestone: v3.8.0
Parent Epic: #1678

Background and Context

The default parallelism for the unit_tests and integration_tests nox sessions is conservatively set to min(cpus, 2). This is a safe default, but it is a significant bottleneck on CI runners with more than 2 cores. The CI Execution Time Optimization Epic (#1678) identifies reducing wall-clock time as a key goal; increasing test parallelism is a direct lever for achieving that.

Expected Behavior

The _default_processes function in noxfile.py should use a higher ceiling — such as min(cpus, 4) or min(cpus, 8) — so that test sessions automatically exploit available cores on multi-core CI runners without requiring manual overrides.

Acceptance Criteria

The _default_processes function returns a value up to min(cpus, 4) (or a higher agreed ceiling) rather than min(cpus, 2).
The unit_tests and integration_tests nox sessions inherit the updated default without any other changes to their configuration.
CI execution time for these sessions is measurably reduced on runners with > 2 cores.
The CI pipeline remains stable: no new test flakiness or resource-contention failures are introduced.

Supporting Information

Parent Epic: #1678 — CI Execution Time Optimization — Timeouts, Concurrency, and Coverage Artifact Sharing
Relevant file: noxfile.py, _default_processes function

Subtasks

Identify the current _default_processes implementation in noxfile.py and confirm the existing ceiling value
Update _default_processes to use min(cpus, 4) (or the agreed ceiling after review)
Update features/ci_workflow_validation.feature (or relevant Behave feature) to assert the new parallelism default if it is tested at the BDD level
Run nox -s unit_tests and nox -s integration_tests locally to confirm no flakiness with the new default
Monitor CI run durations after the change to confirm wall-clock improvement
Verify coverage ≥ 97% via nox -s coverage_report
Run nox (all default sessions) and fix any errors

Definition of Done

This issue is complete when:

All subtasks above are completed and checked off.
A Git commit is created where the first line of the commit message matches the Commit Message in Metadata exactly, followed by a blank line, then additional lines providing relevant details about the implementation.
The commit is pushed to the remote on the branch matching the Branch in Metadata exactly.
The commit is submitted as a pull request to master, reviewed, and merged before this issue is marked done.
All nox stages pass.
Coverage >= 97%.

Automated by CleverAgents Bot
Supervisor: Test Infrastructure | Agent: ca-new-issue-creator

## Metadata - **Branch**: `task/m9-increase-test-parallelism` - **Commit Message**: `chore(nox): increase default parallelism for unit and integration test sessions` - **Milestone**: v3.8.0 - **Parent Epic**: #1678 ## Background and Context The default parallelism for the `unit_tests` and `integration_tests` nox sessions is conservatively set to `min(cpus, 2)`. This is a safe default, but it is a significant bottleneck on CI runners with more than 2 cores. The CI Execution Time Optimization Epic (#1678) identifies reducing wall-clock time as a key goal; increasing test parallelism is a direct lever for achieving that. ## Expected Behavior The `_default_processes` function in `noxfile.py` should use a higher ceiling — such as `min(cpus, 4)` or `min(cpus, 8)` — so that test sessions automatically exploit available cores on multi-core CI runners without requiring manual overrides. ## Acceptance Criteria - The `_default_processes` function returns a value up to `min(cpus, 4)` (or a higher agreed ceiling) rather than `min(cpus, 2)`. - The `unit_tests` and `integration_tests` nox sessions inherit the updated default without any other changes to their configuration. - CI execution time for these sessions is measurably reduced on runners with > 2 cores. - The CI pipeline remains stable: no new test flakiness or resource-contention failures are introduced. ## Supporting Information - Parent Epic: #1678 — CI Execution Time Optimization — Timeouts, Concurrency, and Coverage Artifact Sharing - Relevant file: `noxfile.py`, `_default_processes` function ## Subtasks - [ ] Identify the current `_default_processes` implementation in `noxfile.py` and confirm the existing ceiling value - [ ] Update `_default_processes` to use `min(cpus, 4)` (or the agreed ceiling after review) - [ ] Update `features/ci_workflow_validation.feature` (or relevant Behave feature) to assert the new parallelism default if it is tested at the BDD level - [ ] Run `nox -s unit_tests` and `nox -s integration_tests` locally to confirm no flakiness with the new default - [ ] Monitor CI run durations after the change to confirm wall-clock improvement - [ ] Verify coverage ≥ 97% via `nox -s coverage_report` - [ ] Run `nox` (all default sessions) and fix any errors ## Definition of Done This issue is complete when: - All subtasks above are completed and checked off. - A Git commit is created where the **first line** of the commit message matches the Commit Message in Metadata exactly, followed by a blank line, then additional lines providing relevant details about the implementation. - The commit is pushed to the remote on the branch matching the **Branch** in Metadata exactly. - The commit is submitted as a **pull request** to `master`, reviewed, and **merged** before this issue is marked done. - All nox stages pass. - Coverage >= 97%. --- **Automated by CleverAgents Bot** Supervisor: Test Infrastructure | Agent: ca-new-issue-creator

freemo added this to the v3.8.0 milestone

2026-04-02 23:35:54 +00:00

freemo commented

2026-04-02 23:42:23 +00:00

Author

Owner

Issue triaged by project owner:

State: Verified
MoSCoW: MoSCoW/Could Have — CI/test infrastructure improvement. Could Have.

Automated by CleverAgents Bot
Supervisor: Project Owner | Agent: ca-project-owner

Issue triaged by project owner: - **State**: Verified - **MoSCoW**: MoSCoW/Could Have — CI/test infrastructure improvement. Could Have. --- **Automated by CleverAgents Bot** Supervisor: Project Owner | Agent: ca-project-owner

freemo added the

MoSCoW

Could have

label

2026-04-02 23:42:23 +00:00

freemo added a new dependency

2026-04-02 23:46:21 +00:00

#1678 Epic: CI Execution Time Optimization — Timeouts, Concurrency, and Coverage Artifact Sharing