fix: bound test shard size independently of concurrency

Remove the 32-shard cap so growing inventories do not overfill fixed timeout windows. Keep serial Runtime/Worker/Server shards at most 36 cases and default top-level concurrency at most eight, with explicit --jobs overrides retained. No test exclusions or timeout increases.

Validated the complete Server inventory through the normal runner helpers: 1724 passed, 4 existing ignored, no failures or timeouts; 50 suites including doctests, 580 seconds execution. Runner and naming checks: 26 passed. Root cargo check and formatting/diff checks passed.

docs/development/regression-test-design.md

@@ -53,7 +53,7 @@
 
 ### runner：選択の帳簿と実行引数を照合する
 
-`tools/test.test.ts` の `round-robin shards retain every listed name exactly once at thresholds and the 32-shard cap` は本番parser/sharderへ実形式のlistingを入力し、全名の一意分配と `task.args.slice(3) === selectedNames`、exact/thread/ignore flagsをassertする。`runtime listing persists complete name inventory for large and small binaries` はDeno子でlibtest listingを代替し、本番discovery/executeの保存inventoryを再読取りする。実Rust libtest全体の実行結果照合ではない。
+`tools/test.test.ts` の `round-robin shards retain every listed name without exceeding the case budget` は本番parser/sharderへ実形式のlistingを入力し、全名の一意分配、分割後のケース数上限と `task.args.slice(3) === selectedNames`、exact/thread/ignore flagsをassertする。`runtime listing persists complete name inventory for large and small binaries` はDeno子でlibtest listingを代替し、本番discovery/executeの保存inventoryを再読取りする。実Rust libtest全体の実行結果照合ではない。
 
 `execute preserves live stdout/stderr and times out a group containing a grandchild`、`execute escalates SIGTERM to SIGKILL and reaps a stubborn direct child`、`parent SIGINT/SIGTERM cleans up active groups, reaps children and does not spawn queued commands` は実隔離子プロセスを起動し、PID消滅・保存result・非起動のqueued PIDを観測する。fixtureに独立watchdogがあり、finallyでも回収する。同process group外へ自ら離脱した子孫は対象外。局所入力表を重いrunner全体起動へ移さない。
 

tools/test.test.ts

@@ -106,9 +106,9 @@ function assertThrows(fn: () => unknown) {
   assert(failed, "expected failure");
 }
 
-Deno.test("CPU-derived jobs accommodates concurrent suites within the CLI bound", () => {
-  assert(defaultJobs(24) === 32);
-  assert(defaultJobs(128) === 32);
+Deno.test("default jobs bound suite pressure independently of explicit CLI concurrency", () => {
+  assert(defaultJobs(24) === 8);
+  assert(defaultJobs(128) === 8);
   assert(defaultJobs(6) === 8);
   assert(defaultJobs(1) === 2);
   assert(parseJobs([]) === defaultJobs());
@@ -153,7 +153,7 @@ function listedNames(count: number) {
   return Array.from({ length: count }, (_, i) => `unit::case_${i}`);
 }
 
-Deno.test("round-robin shards retain every listed name exactly once at thresholds and the 32-shard cap", () => {
+Deno.test("round-robin shards retain every listed name without exceeding the case budget", () => {
   const task = {
     name: "pkg/binary",
     command: "/test-binary",
@@ -178,9 +178,10 @@ Deno.test("round-robin shards retain every listed name exactly once at threshold
         "small binaries must be unchanged",
       );
     } else {
-      const expected = Math.min(32, Math.ceil(count / 36));
+      const expected = Math.ceil(count / 36);
       assert(shards.length === expected);
       const lengths = shards.map((shard) => shard.selectedNames.length);
+      assert(Math.max(...lengths) <= 36);
       assert(Math.max(...lengths) - Math.min(...lengths) <= 1);
       shards.forEach((shard, index) => {
         assert(
@@ -212,7 +213,7 @@ Deno.test("global runtime-path packages serialize every normal target without lo
         args: [],
         cwd: "/pkg",
       };
-      for (const count of [0, 1, 59, 72, 73, 1135]) {
+      for (const count of [0, 1, 36, 37, 59, 72, 73, 1135, 1716, 2000]) {
         const names = listedNames(count);
         const shards = shardRustCommand(task, names);
         assert(
@@ -222,7 +223,8 @@ Deno.test("global runtime-path packages serialize every normal target without lo
         for (const shard of shards) {
           const args = shard.task.args;
           assert(args[args.indexOf("--test-threads") + 1] === "1");
-          if (count > 72) {
+          assert(shard.selectedNames.length <= 36);
+          if (count > 36) {
             assert(args[0] === "--exact");
             assert(args.slice(3).join() === shard.selectedNames.join());
           } else {

tools/test.ts

@@ -12,9 +12,10 @@ export const BUILD_TIMEOUT_MS = 1_800_000;
 export const MAX_JOBS = 64;
 
 export function defaultJobs(cpus = availableParallelism()): number {
-  // Leave headroom for internal runners; higher top-level counts can be chosen
-  // explicitly, but are not assumed to improve throughput or timing stability.
-  return Math.min(32, Math.max(1, Math.ceil(cpus * 4 / 3)));
+  // Each suite can spawn its own Runtime, database executors and compiler work.
+  // CPU count alone over-admits these suites and consumes their timeout budgets.
+  // Keep headroom by default; --jobs remains an explicit concurrency override.
+  return Math.min(8, Math.max(1, Math.ceil(cpus * 4 / 3)));
 }
 
 export function parseJobs(args: string[]): number {
@@ -71,7 +72,7 @@ export function shardRustCommand(
   const serial = ["worker", "worker-runtime", "yoi-workspace-server"].includes(
     task.name.split("/")[0],
   );
-  if (names.length <= 72) {
+  if (names.length <= (serial ? 36 : 72)) {
     return [{
       task: serial
         ? { ...task, args: [...task.args, "--test-threads", "1"] }
@@ -79,7 +80,9 @@ export function shardRustCommand(
       selectedNames: [...names],
     }];
   }
-  const count = Math.min(32, Math.ceil(names.length / 36));
+  // Shard size and concurrency are independent: a growing test inventory must
+  // not silently pack more serial cases into the same fixed timeout window.
+  const count = Math.ceil(names.length / 36);
   const shards: string[][] = Array.from({ length: count }, () => []);
   names.forEach((name, index) => shards[index % count].push(name));
   return shards.map((selectedNames, index) => ({