fix(ci): fail on fatal test runner output

test/scripts/test-parallel.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from "vitest";
+import {
+  appendCapturedOutput,
+  hasFatalTestRunOutput,
+  resolveTestRunExitCode,
+} from "../../scripts/test-parallel-utils.mjs";
+
+describe("scripts/test-parallel fatal output guard", () => {
+  it("fails a zero exit when V8 reports an out-of-memory fatal", () => {
+    const output = [
+      "FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory",
+      "node::OOMErrorHandler(char const*, v8::OOMDetails const&)",
+      "[test-parallel] done unit-fast code=0 elapsed=210.9s",
+    ].join("\n");
+
+    expect(hasFatalTestRunOutput(output)).toBe(true);
+    expect(resolveTestRunExitCode({ code: 0, signal: null, output })).toBe(1);
+  });
+
+  it("keeps a clean zero exit green", () => {
+    expect(
+      resolveTestRunExitCode({
+        code: 0,
+        signal: null,
+        output: "Test Files  3 passed (3)",
+      }),
+    ).toBe(0);
+  });
+
+  it("preserves explicit non-zero exits", () => {
+    expect(resolveTestRunExitCode({ code: 2, signal: null, output: "" })).toBe(2);
+  });
+
+  it("keeps only the tail of captured output", () => {
+    const output = appendCapturedOutput("", "abc", 5);
+    expect(appendCapturedOutput(output, "defg", 5)).toBe("cdefg");
+  });
+});