The component-test runner library supports substring filtering with a no-match guard (component-test-runner/src/lib.rs, --only matches no cases is a run error), surfaced by ct-runner (--only, --enumerate) and by the jco driver (runner.mjs only). It is not surfaced by ct-driver, whose arg loop handles only --missing/--target/--jobs/--cases-per-instance/--jsonl (conformance/driver-ct/src/main.rs:59-96) — and ct-driver is the only binary that serves the suite against the wasmtime host.
The incumbent wasmtime adapter had --only ("Run only the cases whose name contains this substring", 7110a99:conformance/adapters/wasmtime/src/main.rs:133-135). Net regression: debugging one failing case on the primary target costs a full-suite run per iteration (~20s+, 16k output lines).
Fix shape: plumb --only (and --enumerate) through ct-driver to the runner library, and add a documented "run one case on one target" example to conformance/README.md — none of the human-mode/filtering ergonomics are documented today, and ct-driver's usage string omits half its existing flags.
The component-test runner library supports substring filtering with a no-match guard (component-test-runner/src/lib.rs,
--only matches no casesis a run error), surfaced by ct-runner (--only,--enumerate) and by the jco driver (runner.mjsonly). It is not surfaced by ct-driver, whose arg loop handles only--missing/--target/--jobs/--cases-per-instance/--jsonl(conformance/driver-ct/src/main.rs:59-96) — and ct-driver is the only binary that serves the suite against the wasmtime host.The incumbent wasmtime adapter had
--only("Run only the cases whose name contains this substring", 7110a99:conformance/adapters/wasmtime/src/main.rs:133-135). Net regression: debugging one failing case on the primary target costs a full-suite run per iteration (~20s+, 16k output lines).Fix shape: plumb
--only(and--enumerate) through ct-driver to the runner library, and add a documented "run one case on one target" example to conformance/README.md — none of the human-mode/filtering ergonomics are documented today, and ct-driver's usage string omits half its existing flags.