Improve parallel suite scheduling and correctness

changelog/unreleased/improve-parallel-suite-scheduling-and-correctness-checks.md

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+---
+title: Improve parallel suite scheduling and correctness checks
+type: bugfix
+authors:
+  - mavam
+  - codex
+created: 2026-02-26T10:19:21.558254Z
+---
+
+Parallel suites are now scheduled more reliably when running with `--jobs > 1`, so interdependent tests (for example publisher/subscriber pairs) start together sooner instead of being delayed behind large backlogs of unrelated tests.
+
+This update also adds an explicit correctness guard for parallel suites: you can set `suite.min_jobs` in `test.yaml` to declare the minimum job count required for valid execution. The run now fails fast if `--jobs` is lower than `suite.min_jobs`, and it also fails hard when a parallel suite cannot reserve at least `min_jobs` workers at runtime (for example under slot contention), instead of proceeding under-provisioned.
+
+In addition, the harness now warns when a parallel suite has more tests than available jobs, making it easier to spot cases where effective suite parallelism is capped by worker count.