fix(test): throttle local vitest under memory pressure

test/scripts/vitest-local-scheduling.test.ts

@@ -31,6 +31,7 @@ describe("vitest local full-suite profile", () => {
       cpuCount: 14,
       loadAverage1m: 14,
       totalMemoryBytes: 48 * 1024 ** 3,
+      freeMemoryBytes: 32 * 1024 ** 3,
     };
 
     expect(shouldUseLargeLocalFullSuiteProfile({}, hostInfo)).toBe(false);
@@ -53,4 +54,62 @@ describe("vitest local full-suite profile", () => {
       vitestMaxWorkers: 1,
     });
   });
+
+  it("serializes local full-suite shards under critical memory pressure", () => {
+    const hostInfo = {
+      cpuCount: 10,
+      loadAverage1m: 0,
+      totalMemoryBytes: 24 * 1024 ** 3,
+      freeMemoryBytes: 3 * 1024 ** 3,
+    };
+
+    expect(resolveLocalVitestScheduling({}, hostInfo, "threads")).toEqual({
+      maxWorkers: 1,
+      fileParallelism: false,
+      throttledBySystem: true,
+    });
+    expect(resolveLocalFullSuiteProfile({}, hostInfo)).toEqual({
+      shardParallelism: 1,
+      vitestMaxWorkers: 1,
+    });
+  });
+
+  it("limits local full-suite shards when memory is tight", () => {
+    const hostInfo = {
+      cpuCount: 10,
+      loadAverage1m: 0,
+      totalMemoryBytes: 24 * 1024 ** 3,
+      freeMemoryBytes: 6 * 1024 ** 3,
+    };
+
+    expect(resolveLocalVitestScheduling({}, hostInfo, "threads")).toEqual({
+      maxWorkers: 2,
+      fileParallelism: true,
+      throttledBySystem: true,
+    });
+    expect(resolveLocalFullSuiteProfile({}, hostInfo)).toEqual({
+      shardParallelism: 2,
+      vitestMaxWorkers: 1,
+    });
+  });
+
+  it("lets explicit system throttle opt-out ignore memory pressure", () => {
+    const env = { OPENCLAW_VITEST_DISABLE_SYSTEM_THROTTLE: "1" };
+    const hostInfo = {
+      cpuCount: 10,
+      loadAverage1m: 0,
+      totalMemoryBytes: 24 * 1024 ** 3,
+      freeMemoryBytes: 3 * 1024 ** 3,
+    };
+
+    expect(resolveLocalVitestScheduling(env, hostInfo, "threads")).toEqual({
+      maxWorkers: 4,
+      fileParallelism: true,
+      throttledBySystem: false,
+    });
+    expect(resolveLocalFullSuiteProfile(env, hostInfo)).toEqual({
+      shardParallelism: 4,
+      vitestMaxWorkers: 1,
+    });
+  });
 });