test: move vitest config regression under active unit surface

src/infra/vitest-config.test.ts

@@ -1,5 +1,6 @@
+import { readFileSync } from "node:fs";
 import { describe, expect, it } from "vitest";
-import baseConfig, { resolveLocalVitestMaxWorkers } from "../vitest.config.ts";
+import baseConfig, { resolveLocalVitestMaxWorkers } from "../../vitest.config.ts";
 
 describe("resolveLocalVitestMaxWorkers", () => {
   it("uses a moderate local worker cap on larger hosts", () => {
@@ -27,7 +28,6 @@ describe("resolveLocalVitestMaxWorkers", () => {
           cpuCount: 10,
           loadAverage1m: 0,
           totalMemoryBytes: 128 * 1024 ** 3,
-          platform: "darwin",
         },
       ),
     ).toBe(2);
@@ -97,3 +97,18 @@ describe("base vitest config", () => {
     expect(baseConfig.test?.setupFiles).toEqual(["test/setup.ts"]);
   });
 });
+
+describe("test scripts", () => {
+  it("keeps test:serial pinned to one worker", () => {
+    const pkg = JSON.parse(
+      readFileSync(new URL("../../package.json", import.meta.url), "utf8"),
+    ) as {
+      scripts?: Record<string, string>;
+    };
+
+    expect(pkg.scripts?.["test:serial"]).toBe(
+      "OPENCLAW_VITEST_MAX_WORKERS=1 vitest run --config vitest.config.ts",
+    );
+    expect(pkg.scripts?.["test:single"]).toBeUndefined();
+  });
+});